He served in the Maryland House of Delegates, representing Allegany County from 1971 to 1974 and District 1B from 1975 to 1986.

[1][2] Byrnes worked as an inspector for the Maryland Motor Vehicle Administration and as a sales manager for W. K. Kellogg Company.

[1][3] Byrnes became a member of the Maryland House of Delegates in 1971 and represented Allegany County from 1971 to 1974 and District 1B from 1975 to 1986.

[3] Byrnes owned his family's hardware store in Frostburg, Maryland until the early 1980s.

[6] Byrnes died on February 26, 1989, at Sacred Heart Hospital in Cumberland, Maryland.