 McCollum attended the Pacific Conservatory of the Performing Arts and has performed in "Jersey Boys" (Chicago company) and with theatres such as Dallas Theatre Center, Utah Shakespearean Festival, Theatreworks (Silicon Valley) in Palo Alto, Indiana Repertory Theatre, GEVA theatre, Syracuse Stage, The Fulton Opera House, Artists Repertory Theatre, Portland Center Stage, Portland Playhouse.In New York McCollum has been seen as Jeffrey in "Jeffrey" at the Sage Theatre and as Nestor le Fripe in "Irma la Douce" at Musicals Tonight.In Los Angeles he was seen as Hedwig in "Hedwig and the Angry Inch", for which he garnered the Los Angeles Drama Critics Circle Award, Backstage's Garland Award for Best actor and won an Ovation Award for best Musical.