He serves on the Steering Committee for The Publishing Triangle, and was also a member of the Executive Council of the International Association of Crime Writers/North American Branch from 2011 to 2015.
After graduating from Union College (Schenectady, New York) he worked in politics and government.
His second novel, Trust Fund Boys was released in 2004 and his third, the Lambda Literary Award-winning When The Stars Come Out, in 2006.
Beginning with his 2009 novel Straight Lies, Byrnes began a series of comic crime capers featuring a hapless gang of gay and lesbian criminals led by partners in life and crime Grant Lambert and Chase LaMarca.
Byrnes has also published short stories in Best Gay Romance 2014; Men of the Mean Streets (2011), a collection of gay noir short stories edited by Greg Herren and J. M. Redmann; Saints & Sinners 2010: New Fiction from the Festival, edited by Amie M. Evans and Paul J. Willis; Fool for Love (2009), a gay romance anthology, edited by Timothy J. Lambert and R. D. Cochrane; and Strange Bedfellows (2000), a book of erotic political fiction, edited by Dominic Santi and Debra Hyde (not to be confused with the 2012 novel.)