Brian Baker, formerly of Minor Threat, formed Dag Nasty with Colin Sears, Roger Marbury and Shawn Brown in 1985. Shortly before the recording of their debut full-length, "Can I Say", Shawn was replaced on vocals by ex-DYS frontman, Dave Smalley, kicking off a revolving door membership that would continue throughout the duration of the band, ultimately leaving Brian as the only original member.

Dag Nasty recorded "Can I Say" in June 1986, and "Wig Out at Denkos" in July 1987, for Dischord Records before moving to Giant Records for the release of "Field Day" in 1988.

The "Can I Say" line-up reformed in 1992 to record "Four on the Floor" for Epitaph Records and again in 2002 to record a full-length for Revelation Records.

In November 2010 Dischord released the long shelved "Dag With Shawn" recording session, featuring the original Dag Nasty line-up with Shawn Brown on vocals. This is essentially the same album that was later re-recorded and released as "Can I Say".

In 2012, the band reunited in its original lineup – guitarist Brian Baker, singer Shawn Brown, drummer Colin Sears, and bassist Roger Marbury – to perform at a benefit for the D.C. punk documentary, Salad Days. Since then, the group has continued to perform on a sporadic basis.

Dischord Records will be releasing a two song 7-inch from Dag Nasty later this year This will be the first tracks in 35 years that Shawn Brown has recorded with band. The 7 inch will feature the tracks "Cold Heart" and "Wanting Nothing", recorded in December 2015 at Inner Ears Studios with Don Zientara and Ian MacKaye.