|Full name||Mark John Byrnes|
|Date of birth||8 February 1982|
|Place of birth||Sydney, Australia|
|Height||1.83 m (6 ft 0 in)|
|Playing position||Centre Back|
|Concord High School|
|2008–2013||APIA Leichhardt Tigers||83||(6)|
|2009||→ Gold Coast United (loan)||1||(0)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 10 October 2013.
‡ National team caps and goals correct as of 6 October 2009
Due to the demise of the National Soccer League after the 2003/2004 season, in July of that year he signed with Finnish club, FC Hämeenlinna. He returned to Australia to form part of Melbourne Victory's A-League 2005-06 squad, but found his chances limited by the emergence of younger defenders Adrian Leijer and Daniel Piorkowski. He was part of Melbourne's A-League championship winning side in 2006-2007. However at the end of the season, on 1 March 2007, he was released by the club.
In 2007, he was announced as a short term signing for Victorian Premier League side Richmond Eagles for three matches. In 2008, Byrnes went on trial with English lower league football clubs Port Vale and Luton Town. He impressed during an overseas pre-season tour to the extent that he would have been offered a contract had he not suffered a minor injury during the last tour match.
With Perth Glory:
- NSL Championship: 2002-03, 2003–04
- (Finnish) FC Hämeenlinna kohtaa MyPan
- Schwarzer's cup pledge
- Selection poser for Victory
- Merrick undecided about Victory team
- Form replaces rotation policy for Victory
- Victory cool on Byrnes the second to go
- New signings in Foxtel Cup
- Blackwell widens search for Leon replacement
- Ellis: Leon sale has left us lacking cover
- Bleiberg signs injury cover for Piorkowski