After attending Illinois State University, Phelps did commercial work and improvisational comedy before meeting his partner Mark Thompson in Birmingham, Alabama in 1986.
In 1991–92, he and Thompson hosted a short-lived NBC TV series, The Adventures of Mark & Brian, based on their radio show.
On August 17, 2012, after 25 years as the KLOS morning team, Mark and Brian signed off the air waves and closed their show.
Longtime 95.5 KLOS Los Angeles morning hosts Mark Thompson and Brian Phelps (Longstanding Local/Regional).
https://www.radiohalloffame.com/2020-inductees On June 14, 2024, Brian debuted the podcast "Be Good Humans" with his new partner, television showrunner Trey Callaway.