In between recording and touring with Rilo Kiley, Jenny contributed vocals to The Postal Service's debut album "Give Up" (2003) and toured as a multi-instrumentalist with the band.

By 2006, Lewis began her solo career with the album "Rabbit Fur Coat" and soon followed it up with 2008's "Acid Tongue", establishing herself as a songwriter moving beyond the confines of indieock into more timeless territory once occupied by artists like Laura Nyro and Emmylou Harris. Joe Levy, editor of Rolling Stone remarked that "Jenny Lewis is the best songwriter working today."
She has collaborated with many other artists and bands, most notably with Elvis Costello, Ryan Adams, T. Bone Burnett and M. Ward. In the summer of 2010, Lewis formed the duo Jenny and Johnny with songwriter Johnathan Rice and released the album "I'm Having Fun Now."

Jenny recently made her debut as a film composer and music supervisor for the new drama "Very Good Girls" starring Dakota Fanning and Elizabeth Olsen. She and Johnathan Rice have also been confirmed as the songwriting team for the upcoming musical/drama, "Song One", which will star Academy Award winner, Anne Hathaway.