Guitarist for the Grammy Award-winning alternative rock band Fun, popular for their #1 hit "We Are Young." He's also the lead singer and songwriter of the band Bleachers.
He was the singer of the band Steel Train in 2002.
He started a relationship with Girls creator Lena Dunham in 2012; however, they later broke up in 2017.
He co-wrote the song "Sweeter Than Fiction" with Taylor Swift for the film One Chance.