Phelan was born in Stoughton, Massachusetts to Dan and Bonnie Phelan. He moved to Houston, Texas with his mother and grandmother Beverly at the age of seven. He began his acting career in various stage productions at the Unicorn Theatre in Houston at age 9. His first national television role was in an episode of the NBC sitcom Sister Kate in 1989 at the age of 13 and followed by small roles in television series such as The Wonder Years, Family Matters and Grand. His first studio film role was in the 1991 drama Toy Soldiers opposite actors Sean Astin, Wil Wheaton and Louis Gossett, Jr.
On March 29, 1994, at age 19, Phelan was involved in an automobile collision when his Toyota Corolla was broadsided three blocks from his home. He suffered a traumatic brain injury which left him comatose for over four years. Phelan died on September 27, 1998 at the age of 23.
