Connelly was the oldest child of W. Michael Connelly, a property developer, and Mary Connelly, a homemaker. According to Connelly, his father was a frustrated artist who encouraged his children to want to succeed in life. W. Michael Connelly himself was a risk taker who alternated success with failure in his pursuit of a career. Connelly's mother was a fan of crime fiction and introduced her son to the world of mystery novels. Today, his mother reads through Connelly’s books at an early stage and helps edit them.

At age 11, Connelly moved with his family from Philadelphia to Fort Lauderdale, Florida and attended St. Thomas Aquinas High School. At age 16, Connelly’s interest in crime and mystery escalated when, on his way home from his work as a hotel dishwasher, he witnessed a man throw an object into a hedge. Connelly was curious and decided to investigate and found that the object was a gun wrapped in a towel. After putting the gun back, he followed the man to a bar and left to go home to tell his father. Later that night, he brought the police down to the bar, but the man was already gone. This event introduced Connelly to the world of police officers and their lives, impressing him with the investigators’ hard faces and the way they worked.

Connelly had planned on following his father’s choice of career as a property developer and started out at the University of Florida in Gainesville as a building-trade major. After two years and grades that were not as good as expected, Connelly went to see Robert Altman’s film The Long Goodbye and was enchanted by what he saw. The film, based on Raymond Chandler’s novel of the same name, inspired Connelly to want to become a mystery writer. Connelly went home and read all of Chandler's works, featuring Philip Marlowe, a detective in Los Angeles during the 1940s and ‘50s, and decided to switch majors to journalism with a minor in creative writing.

After graduating from the University of Florida in 1980, Connelly got a job as a crime beat writer at the Daytona Beach News Journal where he worked for almost two years until he got a job at the Fort Lauderdale News and Sun-Sentinel in 1981. There, he covered the crime beat during the South Florida cocaine wars, an era that brought with it much violence and murder. He stayed with the paper for a few years and in 1986, he and two other reporters spent several months interviewing survivors of the 1985 Delta Flight 191 plane crash, a story which earned Connelly a place as a finalist for the Pulitzer Prize. The honor also brought Connelly a job as a crime reporter at the Los Angeles Times. He moved to California in 1987 with his wife Linda McCaleb, whom he met while in college and married in April 1984.

After moving to Los Angeles, Connelly went to see the High Tower Apartments where Raymond Chandler's famous character, Philip Marlowe, had lived (in The High Window), and Robert Altman had filmed. According to Connelly, the marks of cigarette burns still existed on the walls, something that the current tenant hadn’t dared to paint over. Connelly even got the manager of the building to promise a phone call in case the apartment ever became available. Ten years later, the manager tracked Connelly down and he decided to rent the place. This apartment served as a place to write for several years, but it was more based on the nostalgia of the place than the comfort of it (for example, it didn’t have air conditioning).

After three years at the Los Angeles Times, Connelly wrote his first published novel The Black Echo, after previously writing two unfinished novels that he had not attempted to get published. The novel was sold to Little, Brown to be published in 1992 and won the Mystery Writers of America's Edgar Award for best first novel. The book is partly based on a true crime and is the first one featuring Connelly's primary recurring character, Los Angeles Police Department Detective Hieronymus "Harry" Bosch, a man that, according to Connelly, shares few similarities with the author himself. Connelly named Bosch after the Dutch painter Hieronymus Bosch, known for his paintings full of sin and redemption, including a painting called "Hell", a copy of which hangs on the office wall behind Connelly’s computer. Connelly describes his own work as a big canvas with all the characters of his books floating across it as currents on a painting. Sometime they are bound to collide creating cross currents. This is something that Connelly himself creates by bringing back characters from previous books and letting them play a part in books written five or six years after first being introduced.

Connelly went on to write three more novels about Detective Bosch ... The Black Ice (1993), The Concrete Blonde (1994), and The Last Coyote (1995) ... before quitting his job as a reporter to write full time.

Harry Bosch and Connelly received a good deal of publicity in 1994 when U.S. President Bill Clinton came out of a bookstore carrying a copy of The Concrete Blonde in front of the waiting cameras. According to Connelly, it was a big honor to have such a famous fan and a meeting was set up between the two at the Los Angeles Airport.

After giving up his job as a crime reporter, Connelly was worried that he was going to lose the connections he had built with the LAPD. The stories told by the police officers had served as a great source of information and inspiration for most of his books. But somehow his bond with the Department grew even stronger and the reason for this might be the fact that even though Connelly has been writing about a corrupt and incompetent organization, Bosch has always been portrayed as a good guy. Connelly thinks that many police officers identify with Bosch and the fact that his books are fiction leaves no reason for anyone to get upset.

In 1996, Connelly wrote The Poet, his first book not to feature Bosch; the protagonist was reporter Jack McEvoy. The book was a success and earned Connelly comparisons to author Thomas Harris by reviewers. In 1997, Connelly returned to Bosch in Trunk Music before writing another book, Blood Work (1998) about a different character, FBI agent Terry McCaleb. The book was made into a film in 2002, directed by Clint Eastwood, who also played McCaleb. The story features McCaleb, an agent with a transplanted heart, in pursuit of his donor’s murderer. The book came together after one of Connelly’s friends had a heart transplant and he saw what his friend was going through with survivor's guilt after the surgery. Connelly was pleased with the results of the movie and when asked if he had anything against the changes made to fit the big screen, he simply said; “If you take their money, it’s their turn to tell the story”.

Connelly wrote another book featuring Bosch, Angels Flight (1999), before writing Void Moon (2000), a free-standing book about Cassie Black, a Las Vegas thief. In 2001, A Darkness More Than Night was released, in which Connelly united Bosch and McCaleb to solve a crime together, before releasing two books in 2002. The first, City of Bones, was the eighth Harry Bosch novel, and the other was Chasing the Dime, a non-series novel. In 2001, Connelly left California for Tampa Bay, Florida together with his wife and daughter Callie, so that both Connelly and his wife could be closer to their families. But even though Connelly moved from one coast to the other, his novels still took place in Los Angeles; he feels no desire to write books set in Florida. According to Connelly, after moving to Florida, instead of checking out the places he is writing about, he has to pull them out of his "creative memory".

In 2003, another Bosch novel, Lost Light, was published. With this book, a CD was released, Dark Sacred Night, the Music of Harry Bosch, featuring all the jazz music Bosch supposedly listens to. Connelly himself says he prefers listening to rock and roll, jazz and blues. While writing he listens exclusively to instrumental jazz, though, because it does not have intrusive vocals and because the improvisational playing inspires his writing. The Narrows was published in 2004. This book was a sequel to The Poet, but featured Bosch instead of McEvoy. In the book, the Poet resurfaces after apparently having survived the end of the first book and it’s up to Bosch to catch him. Bosch also has to investigate the death of FBI agent Terry McCaleb, something that at first seemed to be a natural death but turned out to be suicide. Together with this book, a DVD was released called Blue Neon Light: Michael Connelly’s Los Angeles. In the film, Connelly presents some of the places in Los Angeles that are frequently featured in his books.

The Closers was published in May 2005 and was the eleventh Bosch novel. It was followed by The Lincoln Lawyer in October, Connelly’s first legal novel. It featured defense attorney Mickey Haller, Bosch’s half-brother. After releasing Crime Beat in 2006, a non-fiction book about Connelly’s experiences as a crime-reporter, Connelly went back to Bosch in 2006’s Echo Park. This book sets its opening scene in the High Tower Apartment that Connelly rented and wrote from when he first moved to Los Angeles. His next Bosch story, The Overlook, was originally published as a multipart series in the New York Times Magazine. After some editing, it was published as a novel in 2007. In October 2008, Connelly wrote The Brass Verdict, which brought together Bosch and Mickey Haller for the first time. He followed that in May 2009 with The Scarecrow, which brought back McEvoy as the lead character. The latest Bosch novel, 9 Dragons, was released in October 2009.

Connelly was one of the creators and executive producers of Level 9, a science fiction action TV series that aired for 13 episodes in the 2000-2001 season on the UPN television network. His novel Blood Work was adapted into a film in 2002 with a screenplay by Brian Helgeland and direction by Clint Eastwood, who also played the lead role. As of 2009, a film based on the novel Void Moon is in pre-production, with a screenplay by playwright Michael Cristofer, and Connelly himself co-wrote the screenplay for The Equalizer, a pre-production film adaptation of the TV series.

Connelly was the subject of the 2004 video documentary Blue Neon Night: Michael Connelly's Los Angeles. He occasionally makes guest appearances as himself in the ABC comedy/drama TV series Castle. Along with Stephen J. Cannell and James Patterson, he is one of Castle's poker buddies.

Connelly has won every major award given to mystery writers, including the Edgar Award, Anthony Award, Macavity Award, Los Angeles Times Best Mystery/Thriller Award, Shamus Award, Dilys Award, Nero Award, Barry Award, Audie Award, Ridley Award, Maltese Falcon Award (Japan), .38 Caliber Award (France), Grand Prix Award (France) and Premio Bancarella Award (Italy).

Connelly does not like doing any research on his books, he prefers to just write. His main focus is on the book’s characters, not so much on the surroundings. He also uses names of friends or sources for many of the characters in the books as "little tests, to see if they’re really reading my books." When starting a book, the story is not always clear but Connelly has a hunch where it is going. The books usually reference world events, such as September 11 or the beating of Rodney King. Even events that might not be considered as world changing are included in some of the books because they are of personal interest to Connelly. In Angels Flight, Detective Bosch investigates the murder of a eleven-year old girl. This was written during Connelly’s first year as a father of a daughter and it hit close to home. According to Connelly, he didn’t mean to write about the biggest fear of his life, it just came out that way.

Detective Bosch’s life usually changes in harmony with Connelly’s own life. While Connelly moved 3000 miles across the country to Florida, Bosch had some life changing experiences that sent him in a new direction in the book written at this time, City of Bones. After his move to Florida, where he only knew one person, Connelly spent more time at home writing instead of going out. According to Connelly, his "real" job is to write about Bosch, and his purpose in bringing McCaleb and Bosch together in A Darkness More Than Night was to use McCaleb as a tool to look at Bosch from another perspective and keep the character interesting.

Note: Every character on this list, including those who have been the main characters of their own books, has appeared in a Harry Bosch book.

Main characters

• Hieronymus “Harry” Bosch — a Los Angeles Police Department detective who retired and became a private investigator for a couple of novels, before returning to LAPD's Open Unsolved Unit, a fictional unit based on LAPD's actual Cold Case Homicide Unit, and later the Robbery Homicide Division (RHD) Homicide Special Unit.
• Michael "Mickey" Haller — criminal defense attorney; Harry Bosch's half-brother
• Terrell "Terry" McCaleb — former FBI agent
• Jack McEvoy — crime reporter, brother of one of the Poet's victims
• Cassidy "Cassie" Black — burglar and ex-con
• Rachel Walling — FBI agent, who dated Bosch and now dates McEvoy

Other characters

Each of these characters has appeared in at least two novels of Connelly's.

• Irvin S. Irving — former LAPD Deputy Chief and Bosch's chief nemesis in the department; now an L.A. city councilman
• Francis "Frankie" Sheehan — Bosch's original partner in Robbery-Homicide Division (deceased)
• Jerry "Jed" Edgar — Bosch's former partner in Hollywood Homicide squad; now a detective leader there
• Kizmin "Kiz" Rider — Bosch's former partner in Hollywood Homicide squad and the RHD Open-Unsolved Unit; now an aide to the L.A. chief of police
• Ignacio "Iggy" Ferras — Bosch's former partner in the RHD Homicide Special Unit (deceased)
• John Chastain — former LAPD Internal Affairs detective (deceased)
• Harvey "Ninety-Eight" Pounds — Bosch's ex-supervisor in Hollywood Homicide squad (deceased)
• Lieutenant Grace "Bullets" Billets — Pounds' successor as Bosch's supervisor in Hollywood Homicide squad
• Eleanor Wish — ex-FBI agent, ex-con and Bosch's ex-wife, mother of Bosch's daughter Maddie; moved to Hong Kong (deceased)
• Robert "Bob" Backus — ex-FBI agent (deceased)
• Roy Lindell (aka "Luke Goshen") — FBI agent
• Janis Langwiser — a criminal defense attorney
• Keisha Russell — Los Angeles Times reporter, now based in D.C., who occasionally provided information for Bosch; McEvoy's ex-wife
• Thelma Kibble — Cassie Black's parole officer
• Maddie Bosch — daughter of Bosch and Eleanor Wish; now lives with Bosch in L.A.
• Jaye Winston — Detective, works alongside both Bosch and McCaleb in 'Blood Work' and 'A Darkness more than Night'

Fiction books

Harry Bosch series

1. The Black Echo (1992)
2. The Black Ice (1993)
3. The Concrete Blonde (1994)
4. The Last Coyote (1995)
5. Trunk Music (1997)
6. Angels Flight (1999)
7. A Darkness More Than Night (2001) — also featuring Terry McCaleb and Jack McEvoy
8. City of Bones (2002)
9. Lost Light (2003)
10. The Narrows (2004) — also featuring Rachel Walling and Terry McCaleb plus a short appearance by Cassidy Black.
11. The Closers (2005)
12. Echo Park (2006) — also featuring Rachel Walling
13. The Overlook (2007) — also featuring Rachel Walling
14. 9 Dragons (2009)

Mickey Haller series

1. The Lincoln Lawyer (2005)
2. The Brass Verdict (2008) — featuring Harry Bosch and Jack McEvoy
3. The Reversal (2010) — also featuring Harry Bosch
4. The Fifth Witness (2011)

Jack McEvoy series

• The Poet (1996) — featuring Jack McEvoy and Rachel Walling
• The Scarecrow (2009) — featuring Jack McEvoy and Rachel Walling

Other novels

• Blood Work (1998) — featuring Terry McCaleb
• Void Moon (2000) — featuring Cassie Black
• Chasing the Dime (2002) — featuring Henry Pierce

whether it will be part of a series or standalone

Editor

• The Best American Mystery Stories 2003 (2003) — collected short stories.
• Murder In Vegas (2005) — collected short stories.
• In the Shadow of the Master (2009) — collected short stories by Edgar Allan Poe re-written by current mystery writers including Sue Grafton and Stephen King

Short stories

• "Two-Bagger" — in Murderers' Row (2001) and The Best American Mystery Stories 2002 (2002).
• "Cahoots" — in Measures of Poison (2002)
• "After Midnight" — in Men from Boys (2003)
• "Christmas Even" — in Murder...and All That Jazz (2004); a Harry Bosch story (partner: Jerry Edgar)
• "Cielo Azul" — in Dangerous Women (2005); a Harry Bosch and Terry McCaleb story (backstory to A Darkness More than Night)
• One story published anonymously in The Secret Society Of Demolition Writers (2005)
• "Angle of Investigation" — in Plots with Guns (2005) and The Penguin Book Of Crime Stories (2007) — continuation of The Closers; with Harry Bosch (partner: Kiz Rider)
• "Mulholland Dive" — in Los Angeles Noir (2007), Prisoner of Memory (2008), The Best American Mystery Stories (2008), and A Prisoner of Memory and 24 of the Year's Finest Crime and Mystery Stories (2008)
• "Suicide Run" — in Hollywood and Crime (2007); featuring Harry Bosch
• "One Dollar Jackpot" — in Dead Man's Hand (2007); featuring Harry Bosch
• "Father's Day" — in The Blue Religion (2008), and The Best American Mystery Stories (2009); a Harry Bosch story (partner: Ignacio Ferras)
• "Blue and Black" — in Hook, Line & Sinister (2010); a Harry Bosch story, with Rachel Walling
• "The Perfect Triangle" — in The Dark End of the Street (2010); a Mickey Haller story

Non-fiction books

• Crime Beat (2006), collected journalism from the Sun-Sentinel and Los Angeles Times

Videography

• Level 9 (2001) — co-creator and co-executive producer