Byrne made his Bohs debut in the 1979 FAI League Cup final win over Shamrock Rovers on 22 March 1979.
He was the top scorer in the 1986–87 League of Ireland Premier Division season [3][4] and made 6 appearances in European competition.
Transfer talks with Saint-Étienne[5] and Feyenoord did not work out,[6] so after 72 goals in 146 games, in January 1988 he signed for ADO Den Haag thus ending an extraordinarily successful period at Rovers.
He briefly re-signed for Rovers again in July 1988 but after 3 goals in 6 games he left for Huddersfield Town the following month for £20,000.
He had two more spells at Shels and also represented Dundalk, Monaghan United, St. James's Gate (one game) and Athlone Town during his career.