Walker, with fellow composer/lyricist Gary Adler and book writer Kevin Del Aguila, wrote and created the Off-Broadway musical Altar Boyz,[2] which won the 2005 Outer Critics Circle Award for Best Off-Broadway Musical.[3] Additionally, the show was nominated for seven Drama Desk Awards (including two each for Walker and Adler for Best Music and for Best Lyrics)[4] and four Lucille Lortel Awards including Best Off-Broadway Musical. The show ran for 2,032 performances, making it the ninth-longest running Off-Broadway musical of all time.[5] It has been translated into multiple languages to be performed around the world.
From 2005 through 2008, Walker composer numerous songs for the Emmy-nominated Disney Channel TV Series Johnny and the Sprites, becoming the music director and supervisor for Season 2 of the show. In this capacity, Walker served as the lead composer, oversaw a team of theatre composers who wrote the original songs for each episode, and developed the stories for each of 26 scripts for the series. He also arranged, orchestrated, and produced the recordings of the songs and co-produced the CD for the series. Season 2 of Johnny and the Sprites received four Daytime Emmy Award nominations, including one for Outstanding Pre-School Children's Series. His involvement lead to his writing original music and lyrics for the Nick Jr. Channel television show Olivia.