McDonald graduated from St. Juliana Catholic Elementary School in Fullerton, California and later went to Servite High School in Anaheim, California, and graduated from the University of Southern California with a business degree. While at USC, he was a member of the Phi Delta Theta fraternity. He worked as a loan officer at a bank in Los Angeles.

After college, a friend took McDonald to see an improv comedy show at Groundling Theater. McDonald quit his job at the bank and enrolled in Groundling's improv program. He was a member of the troupe from 1992 to 1997. During that time, he was also involved in writing and directing films for Roger Corman.

Later on, McDonald would guest star in such shows as Seinfeld (in two episodes playing two different parts), Just Shoot Me!, Family Matters, Scrubs and NewsRadio. He also made brief appearances in all three Austin Powers movies. McDonald had a starring role with Will Forte and Nicole Sullivan on the short-lived MTV show Clone High as the voice of Gandhi.

Stand Up Comedy

Michael is currently touring at stand up comedy clubs across the country. His stand-up comedy special Michael McDonald: Model Citizen premiered on SHOWTIME on October 9, 2010. Filmed in Orange County at the OC Pavilion, it has been described as "Part stand-up comedy, part one man show, this special is for anyone who — like Michael — finds humor in the strange world all around us."

Cougar Town

McDonald is a writer, director, and producer of the ABC show Cougar Town

Has directed 5 episodes of the show

• Letting You Go, 2010
• Everything Man, 2010
• When a Kid Goes Bad, 2010
• Stop Dragging My Heart Around, 2010
• Don't Come Around Here No More, 2009

Wrote the Episode of Cougar Town entitled, " Wake Up Time"

MADtv

McDonald joined the cast of MADtv in 1998, and has since become the cast member with the longest tenure in the history of the show (10 seasons). He has performed several recurring characters, including Stuart Larkin, Rusty Miller, Marvin Tikvah, Sean Gidcomb, Bible Dude, Mofaz the Depressed Persian Tow Truck Driver, and F. Michael McKrofsky of "Real M*********ing Talk". McDonald also performs impressions of celebrities and well-known figures, including Al Gore, Bob Barker, John Kerry, Dr. Phil, Bill O'Reilly, Maury Povich, Chris Martin, Steve Jobs, Mel Gibson, Chris Hansen, Roy Horn, Ozzy Osbourne, John Ramsey, Freddie Prinze, Jr., J. K. Simmons (as Mac McGuff, Juno's father), William Petersen (as Gil Grissom), Jack Coleman (as Noah Bennet), Hugh Laurie (as Gregory House), Hugh Beaumont (as Ward Cleaver), Sarah Jessica Parker (as Carrie Bradshaw), Dr. Drew, Adam Sandler, Howie Mandel, Dick Cheney, Clint Eastwood, Gray Davis, Simon Cowell, JC Chasez, Bruce Jenner, Michael Richards, Chris Burke, Charlie Sheen (as Charlie Harper ), David Schwimmer (as Ross Geller), Jeff Probst, Tim Gunn (Project Runway), Howard K. Stern, Tommy Lee, Bob Goen, Criss Angel, Jeff Foxworthy, Saddam Hussein, Matthew Good, Daniel Powter, Larry David, Barry Gibb, and Brad Garrett.

McDonald was the last member of the cast to have appeared on the show during the 1990's, and the last cast member to have been born in the 1960s.

After 10 years on MADtv, Michael left the show, but was still a contributing writer/director.

McDonald is the only cast member to have a BEST OF Compilation Episode on MADtv.