Jarkko Nieminen won two singles and three doubles ATP tournaments, reaching the 13th world position on July 10, 2006, the best overall position for a Finnish tennis player. He is also so far the only Finn to have won at least one ATP singles tournament and to have reached the quarterfinals of a Grand Slam tournament.

In 2012 he represented his country at the London Olympics, without winning any medals.

His best performances in Grand Slam tournaments were the quarterfinals, reached at the US Open 2005, Wimbledon 2006 and the Australian Open 2008. On June 23, 2015, he announced his retirement from professional tennis, with participation in the Stockholm as his last event.

His wife Anu is a Finnish badminton player.