Topher Grace was born Christopher John Grace in New York City, New York, to Pat, a schoolmaster's assistant, and John Grace, an executive. He was raised in Darien, Connecticut. He attended boarding school in New Hampshire for two years, where he began his acting career in such musicals as "Joseph and the Amazing Technicolor Dreamcoat" and "The Pirates of Penzance." He also tried his first shot at directing with a choose-your-own-adventure-style movie starring his classmates. He hated being called Chris in school, so he changed it to Topher as time went on. He attended New Hampshire's Brewster Academy and the University of Southern California.

Grace dropped out of USC to start his show business career in That '70s Show (1998) at age 20. He was cast in that show because the show's creators, Bonnie Turner and Terry Turner, saw him act in a high-school play--their daughter attended same high school. Apart from school plays, Grace had absolutely no acting experience before landing the role of Eric Forman.