He portrayed the teenage Andy Barclay in Child's Play 3, Ridley Freeborn in Dungeons & Dragons, and Jimmy Olsen in the American television series Lois & Clark: The New Adventures of Superman.

Whalin worked as an actor from the age of eleven, when he appeared in a production of the play The Little Prince at San Francisco's Victoria Theatre.

[4] His first TV role was on General Hospital, after he caught the attention of a casting director who was giving an acting class.

[citation needed] Whalin was cast as the young Daily Planet photographer Jimmy Olsen in the TV series Lois & Clark: The New Adventures of Superman from 1994 to 1997.

Whalin quit acting in 2009 to work as a social studies/drama[7] teacher and administrator at The Learning Castle and La Cañada Preparatory, his mother's exclusive schools in the Los Angeles area.