He has written and produced for various artists, including Avril Lavigne, Daughtry, Jason Derulo, Christina Perri, Gavin Degraw, and Hot Chelle Rae.

Johnson is credited with having several RIAA-certified multi-platinum songs ("The Other Side", "Here's to Never Growing Up", "Two Is Better Than One" (with Taylor Swift), "Love Drunk", "The Great Escape," "You'll Always Find Your Way Back Home").

The band, which consists of Johnson, Paul DiGiovanni, John Keefe, and Morgan Dorr (as of 2011) was formed in Boston, Massachusetts in 2005.

Johnson co-wrote, with Taylor Swift, the song "You'll Always Find Your Way Back Home" from the Hannah Montana Movie soundtrack.

[7] Most recently, Johnson produced and co-wrote Avril Lavigne's "Here's to Never Growing Up", Jason Derulo's "The Other Side",[8] Karmin's "Acapella", Mike Posner's "The Way It Used To Be", Gavin Degraw's "Best I Ever Had", and Christina Perri's "Human".