Dan Sullivan is best known by his alter-ego, Dan Panic and for a time was considered one of the top pop-punk drummers around. As Dan Panic, he played drums for Screeching Weasel from 1991 until 1997. Dan Panic also played drums live with the Queers for a 1994 tour and appeared on their Beat Off LP (also released in 1994). Dan Sullivan got his start playing drums for the suburban band Ivy League, who formed in the late '80s and broke up in 1991. He also performed with the Riverdales from 1995 until 1997. After his time with Screeching Weasel was through, he toured as a member of the Groovie Ghoulies and Pansy Division. In the late '90s, Dan and his wife moved to San Francisco where he performed with the Plus Ones, a reunited Avengers (sometimes called the Scavengers), Beulah and The Red Verse. After taking an extended break from playing, Dan now occasionally appears with the Indiana-based pop-punk band Squirtgun, which is led by former Screeching Weasel producer and one-time bassist Mass Giorgini. In a 2020 chat with former Screeching Weasel members Jughead and Dan Schafer, Dan revealed that he works as a manager of two wine and cheese shops in California.
Dan's younger sister, Kelly, was, for a time, co-lead vocalist for 8 Bark and later sang and played bass for the Wisconsin-based pop-punk band The Fosters (whose name was inspired by the singer of Dan's former band)..