He played guitar for a band named "Annie's Autograph".
Parents, June and John Gallagher, are musicians. Has played in several bands and performs occasionally as a singer/songwriter.
John originated the role of Jeff in David Lindsay Abaire's hit play "Kimberly Akimbo"
Played in a band called Old Springs Pike which plays relatively frequent gigs at various locations primarily in New York City.
Won a Tony Award in 2007 for his portrayal of Moritz in "Spring Awakening".
Younger brother of actress Jaime Gallagher.
Brought the role of Johnny/Jesus of Suburbia to Broadway as American Idiot begins previews March 2010 and opens on April 20, 2010 [March 2010]
In London rehearsing for the West End premiere of David Lindsay Abaire's hit play "Fuddy Meers". [March 2004]
Currently playing the role of Lee in the critically acclaimed Jez Butterworth play "Jerusalem" at the Music Box Theatre in New York City. This production is a 16 week limited engagement and opened on April 21, 2011 after starting previews on April 2nd. [April 2011]
Performing in "Farragut North" at Atlantic Theatre Company in Chelsea, New York. [November 2008]
Left the role of Johnny/Jesus of Suburbia in Green Day's American Idiot on February 27, 2011 to pursue a new role in the acclaimed play Jerusalem. [February 2011]
Now performing as Johnny in Green Day's "American Idiot" at the Berkeley Repertory Theatre, Berkeley, California. [September 2009]
Performing as Moritz in Spring Awakening on Broadway. [December 2006]
He was in a relationship with Aubrey Plaza in high school in Wilmington, DE. They did community theatre together and were each other's first love. In an interview with Nerve, Plaza revealed that he "sang a song that he wrote for [her] in front of his parents and a bunch of people at an Irish pub when [they] were thirteen. That was how he asked [her] out... That was magical." In a Vulture interview, Gallagher gushed about the "sweet things" Plaza had said in the article, revealing that their "families are close" and that they "still keep in touch.".