Ganea debuted in Liga I (Divizia A at that time) with FC Brașov in 1994. He went on to play for a number of clubs in Romanian football over the next five years. He joined Rapid Bucharest in January 1999, where he scored 11 goals in the remainder of the season to fire the club to the league championship. He finished that season with 28 goals overall, making him the leading goalscorer.
This form won him a move to Bundesliga side VfB Stuttgart in the summer of 1999. He remained in Germany for four seasons and tasted UEFA Cup action, but was never a regular starter. He moved to Turkish top flight club Bursaspor in June 2003 on a free transfer, but stayed there for just six months before moving to England.
The striker joined Premier League club Wolverhampton Wanderers in December 2003 after his contract in Turkey was cancelled by mutual consent. He scored three Premier League goals during the 2003–04 season – against eventual champions Arsenal, Leeds and Newcastle – but could not prevent relegation.
He remained with the club for two seasons in the second tier, mostly under the managerialship of Glenn Hoddle. The first of these years was written off after suffering cruciate knee ligament injury on a pre-season tour of Norway. He recovered for the 2005–06 season but never held down a regular starting place, and was released as his contract expired at the end of the campaign.
He moved back to Romania, with Dinamo Bucharest on an initial one-year deal. However, just six months later, Ganea broke this contract to rejoin Rapid Bucharest on a record €350,000 ($462,000) a season. Although contracted to the end of 2009 with Rapid, Ganea left on a free transfer in June 2007 for FC Timişoara, despite the fact that he could have earned up to €1 million a season through bonuses at Rapid.