Career
He played as a centre back for Football Club Volendam, Leeds United, Bradford City and Royal Bank of Canada Roosendaal. He was signed for Leeds United by the then manager George Graham from Football Club Volendam for £1m in January 1997 to try to shore up the defence. He became a regular in the side until the end of the 1996-1997 season.
In 1998-1999 he was once again a first choice centre-back, above David Wetherall but a challenge by Nicolas Anelka, then playing for Arsenal, kept him out via ligament damage until 2000.
He failed to make another appearance for Leeds United and was sold to Bradford City in the summer of 2000 to help their dog fight against relegation. He stayed there until 2003, scoring twice against Newcastle United and Nottingham Forest, when his contract was not renewed and he moved to Royal Bank of Canada Roosendaal before eventually retiring in the summer of 2007.
While at Leeds he picked up the nickname "The Terminator" from the fans due to his bulky physique and height. Before working as assistant manager of Nippon Electric Corporation and manager of amateur side RKSV Halsteren, Molenaar was appointed manager of Eerste Divisie side Football Club Volendam from July 2015.