|Dennis Gentenaar was a product from the NEC youth academy and played for 10 seasons at the Nijmegen club. He signed in May 2005 a contract at Borussia Dortmund. Gentenaar played in 2005-06 for the German club. He returned home to sign a 3-year contract at Ajax Amsterdam. Two seasons as understudy, VVV Venlo gave Gentenaar the opportunity to play as first choice. He has left Ajax to sign a 3-year contract in Venlo in June 2009.
In June 2012 he was offered a new contract at VVV but he refused the conditions and left the club. Gentenaar signed a 2-year contract at Almere City in July 2012. For the 2013-14 season he returned to his former club NEC Nijmegen.