Michael Greenfield (born 13 September 1985 in Liverpool, New South Wales Australia) is a former rugby league player who previously played for the Melbourne Storm, Cronulla Sharks, South Sydney Rabbitohs and the St George Illawarra Dragons in the NRL. He plays as a Prop or in the Second Row. He was a member of the Dragons' 2011 World Club Challenge-winning team.
While attending Westfields Sports High School, Greenfield played for the Australian Schoolboys team in 2003. He started playing rugby league relatively late in his life, having previously played basketball.
Greenfield started his first-grade career with the Cronulla Sharks, for whom he played one NRL match in 2004. He then moved to the South Sydney Rabbitohs, playing in 24 NRL matches over four seasons. He signed for the St George Illawarra Dragons from the 2010 season, and later extended his contract through the 2011 season.
Greenfield was selected to play in the 2011 World Club Challenge on 27 February 2011 at DW Stadium against the 2010 Super League premiers, Wigan Warriors. St George Illawarra Dragons went on to win the game 21-15. At the end of the 2011 season, he was released from his contract with St George. During his time at Melbourne, he suffered an injury from a shoulder charge which was bad enough to prevent him from continuing to play.