His first play, Retail Sluts, debuted in 1998 in New York City. Over his career, Spitz wrote and co-produced dozens of off-Broadway plays, including (The Rise and Fall of) The Farewell Drugs, “…Worry, Baby,” The Hobo Got Too High, I Wanna Be Adored, Shyness is Nice and Gravity Always Wins.
Spitz released his first book, We Got the Neutron Bomb: The Untold Story of L.A. Punk, in 2001. Co-authored with Brendan Mullen, the title covers the rise of the Hollywood punk scene of the mid and late 1970s, and the hardcore and new wave scenes of the early ’80s. Spitz's autobiographical novel How Soon Is Never? -- about two rock writers attempting to reunite The Smiths -- arrived in 2013. His other titles include the biographies Nobody Likes You: Inside the Turbulent Life, Times, and Music of Green Day and Bowie: A Biography.
In addition to Spin, Spitz contributed to publications such as Rolling Stone, Maxim, Nylon, Vanity Fair, New York Magazine, TV Guide and The New York Times.
At the time of this death, Spitz was a weekly culture writer for Salon.com. He was also working on a cultural history of rock 'n' roll cinema, entitled Loud Pictures, according to his website.