Timothy Zahn was born in Chicago, Illinois, in 1951, and grew up in Lombard, a suburb west of the city. He attended college at Michigan State University, and aquired a B.S. in physics from it in 1973. He went on to work towards his doctorate at the University of Illinois' Champaign-Urbana campus, earning an M.S. in physics in 1975.

In 1975, Zahn also began writing science fiction as a hobby. In the winter of 1978, he sold his first story, "Ernie," to Analog while still trying to work towards a career as a physicist. Zahn's second story, "The Dreamsender," sold in mid-1979, on the same day that his thesis advisor died.

Because he had to take on a new thesis advisor and a new project, Zahn was forced to rework towards his doctorate from scratch. In August of 1979, Timothy Zahn was married to a woman called Anna. By 1980, he had become more and more interested in writing, and disinterested in physics. He finally left the University of Illinois to try his hand at science fiction authoring full-time. While Zahn concentrated fully on his new writing career, his wife supported them both.

For the first year, Zahn's goal for total income was one thousand dollars. He sold eighteen stories that year, and brough in twice his goal! It was a long time before he was able to make enough money to live off of, but in 1984, he finally did it.

In 1982, he was nominated for a Hugo award for his short story "Pawn's Gambit" (Analog, March 1982). In 1983 he was actually got the Hugo for "Cascade Point" ((Analog, December 1983), and was nominated again the next year for "Return to the Fold" ((Analog, September 1984). In 1991, Zahn made history with the publication of his New York Times #1 Bestselling Star Wars Thrawn Trilogy (Heir to the Empire, 1991; Dark Force Rising, 1992; The Last Command. 1993), This classic series was the first real Star Wars story to be published in over eight years. Zahn's Conqueror's Trilogy was published beginning in 1994 (Conqueror's Pride, 1994; Conqueror's Heritage, 1995; Conqueror's Legacy, 1996). He has since written several more short stories to add to the more than sixty short stories previously published, contributed two more novels to Bantam Books' Star Wars series. Timothy Zahn has also worked with Michael A. Stackpole in coauthoring some Star Wars short stories, and one novella called Interlude at Darkknell

Timothy Zahn currently resides on the Oregon coast.