Mercer’s music has been featured in the films Married to the Mob, Something Wild (which featured a performance by the Feelies credited as "The Willies"), Prelude to a Kiss, The Truth about Charlie and The Squid and the Whale. Glenn’s television credits include Dawson’s Creek, Party of Five and The Real World. He has also recorded with Feelies offshoots the Trypes, Yung Wu, the Willies and Wake Ooloo.
His first solo record, Wheels In Motion, was released by Pravda Records on June 5, 2007. Performers on the record include ex-Feelies drummers and percussionists Stanley Demeski, Vinny DeNunzio, Dave Weckerman and Anton Fier, as well as ex-Feelies and Trypes bassist Brenda Sauter.
Mercer's live band includes Greg Feller (drums), Dave Weckerman (percussion), Adam Berardo (guitar), John Baumgartner (keyboards) and Bob Torsello of Shrubs (bass).