He was a journalist at the Buffalo Courier-Express (Buffalo, New York) 1974-1978 and bureau chief 1976-1978. He was a staff writer at the Providence Journal-Bulletin (Providence, Rhode Island) 1979-1981. He joined The Los Angeles Times as a financial writer 1981-1983, and was its financial correspondent in New York City 1982-1988, Nairobi bureau chief 1988-1993, Moscow correspondent 1993-1994. He was a financial staff writer, editor, and columnist at the Times 1994-2006.More recently, he began writing a column about business and economic issues in the US West Coast.

He won Silver Gavel award from the American Bar Association and the Overseas Press Club cited his reporting on East African issues. In 1996 he was a finalist for two Pulitzer Prizes, for his reporting on health care issues in California and his reporting on a major entertainment merger between Disney and ABC.

Along with Times Staff Writer Chuck Philips, Hiltzik won the 1999 Pulitzer Prize for the articles they wrote on corruption and payola in the music industry.In 2004, Hiltzik won a Gerald Loeb Award for his contributions to financial journalism.In the mid-2000s, Hiltzik was suspended from posting to his blog on the LA Times (entitled "The Golden State") "... after he admitted...he'd been posting there, as well as on other sites, under false names. He used the pseudonyms to attack online conservative nemeses like Hugh Hewitt and L.A. prosecutor Patrick Frey (who eventually exposed him)."