Machen born Mark was educated at Bedwas School. Made his Newport RFC debut vs London Welsh at Rodney Parade 12th April 1993 (Won 40 v 15). From 1992-93 to 1999-2000 he made 150 appearances and scored 25 tries for Newport RFC and won the Arthur Boucher Award in 1994-95. He left Newport in July 2000 to join Caerphilly and rejoined Newport in 2005-06. He made his 150th app in South Africa vs Natal Sharks on 3rd June 2000 and by the end 2005-06 had made a total of 181 appearances for Newport RFC scoring 27 tries. Mark has also made around 100 appearances or more for each of Machen RFC and Caerphilly RFC.
Made his 200th appearance at Rodney Parade on 24th March 2007 as Newport completed the double over Ebbw Vale (Won 22 v 11).
Mark went on to make his 250th appearance for Newport in a SWALEC cup game against Bridgend on 24th January 2009 (Won 44 v 7).
Announced his retirement as a player at the end of the 2009-10 season. His last, and 287th appearance for Newport, was against Swansea at St. Helens in the Welsh Premiership Play-Off Semi Final on 17th May 2010 (Lost 31 v 17).
Following well wishers' comments on 'Talk Newport' Mark posted the following appreciation:-
"I'd like to thank you all for your very kind messages and for your support over the years. I am very proud of my association with Newport RFC and sad that I won't be pulling the Black and Amber Jersey on again. During my time at Rodney parade I have played with some fantastic players. Early days there was Muddy, Moseley, Goodey, Gareth Rees then came Goughie, Voyley, Snowy followed by Howarth and Teichmann and latterly Dai Pats, Pooley and Hilly to name but a few."
"I've worked under some great coaches, Roger Powell who signed me from Machen. The one and only Junna who had a massive influence on me, Steve Fenwick, Pierre Villepreux (or Villeprix as Junna called him), Allan Lewis, then Dai Rees, Hembrow and Sven all with different qualities and ideas."
"I played in the first ever professional Newport team v Aberavon in 96 I think, but feel I have had the best of both worlds experiencing the old traditional rugby environment and today's professional era. (I think, preferring the former)."
"Tours to South Africa and Canada are among the many memories and experiences that will stay with me forever as will my many friends I have made along the way and for this I owe a massive thank you to Newport RFC and everyone involved in this great club."
"I shall look forward to seeing you on the terraces and in the club next season."