He represented the riding of Cape St. Francis in the Newfoundland and Labrador House of Assembly.
Formerly the mayor of Logy Bay-Middle Cove-Outer Cove from 1986 to 1993, he was first elected to the House in the 1993 provincial election representing the district of St. John's East Extern.
He moved to the redistricted riding of Cape St. Francis in the 1996 election, and represented that district until his death.
He won five consecutive elections (1993, 1996, 1999, 2003, 2007) Byrne had been treated during the 1990s for a tumour on his pituitary gland and died on June 4, 2008.
[1] On October 24, 2008, the Jack Byrne Arena opened in Torbay, Newfoundland and Labrador with an appreciation night dedicated to Jack Byrne, his wife Bridget and son Matthew dropped the first puck in the new stadium for a hockey game between Torbay and Bell Island.