Cristea started football in his home town and made his debut in the Divizia A in 2001, for local club FCM Bacău.
His 2004 transfer to Steaua Bucureşti cost the Bucharest giants over $1 million. However, Cristea did not manage to earn a first-team place there, despite scoring two goals that eliminated Valencia CF in the 2004–05 UEFA Cup season. He was put on the transfer list in the summer of 2006.
Cristea moved to fellow Liga I club Politehnica Timişoara, in a swap which saw Gigel Coman move to Steaua Bucureşti. After failing to impress at Politehnica Timişoara, he was loaned to Politehnica Iaşi for the second part of the 2007–08 season, where he had a great part in saving the team from relegation, with man of the match performances against CFR Cluj and his former team, Steaua Bucureşti.
On 9 May 2008, Cristea signed a five-year contract with Dinamo, just six days before turning 24. He called the transfer "a birthday present" and joined Dinamo after the summer holiday. He started scoring for the red and white team in the friendly games they played in pre-season. Cristea played only the first half on the season for Dinamo, netting two goals in eight matches and entering Dinamo's history by scoring the goal that brought the 1.000th victory of the team in all-time domestic championship, against Farul Constanta.
He went on loan in the winter transfer window to Poli Iasi, where he was very well received and scored seven times in 15 games, goals which proved crucial in helping the team continue in the first division. Upon his return, he became a very important player, scoring goals that brought significant victories in Liga I and Europa League. He was the top scorer of the Romanian league in the 2009–10 season with 16 goals.
On 16 January 2011, Karlsruhe signed Cristea in the attempt of avoiding the relegation. On 13 February, Cristea scored two goals against the leader of Second Bundesliga, Hertha BSC. These were his first goals on this new club. On 27 February, he scored the last goal of the game in the 1–4 loss against FC Ingolstadt 04, after coming from bench. On 11 March, Cristea scored the first goal of the match in Karlsruhe-Duisburg, 3–1 final score. On 15 May, in the last round of the Second Bundesliga, the Romanian striker saved his club from relegation, scoring a brace in the 3–2 win against Union Berlin. The next season Karlsruhe were relegated after a play-off and Cristea became a free agent.
Initially, Cristea wanted to stay in Germany, where he had offers from Ingolstadt and Energie Cottbus. But Dinamo approached him and Cristea accepted to return to Bucharest where he had the chance to work again with Dario Bonetti, the coach that managed Dinamo the last time Cristea was under contract with the Red Dogs.
On 22 June 2014, Cristea signed a one-year contract with Azerbaijan Premier League side Gabala FK. In December of the same year Cristea had his contract with Gabala terminated. Following his release from Gabala, Cristea signed with Lega Pro side U.S. Salernitana 1919 until the end of the season.
In February 2016, after his experiences in the lower leagues of Italy, Cristea returned to Romania to joing Liga I club CSMS Iași. He subsequently signed a one and a half year contract with his former team, as FC Politehnica Iași restructured as CSM Politehnica Iași after the club declared bankruptcy in 2010. Cristea scored 7 goals in 17 games in the second half of the 2015–16 Liga I and helped CSM Politehnica Iași qualify for the 2016–17 Europa League qualifying phase for the first time in their history. He then opened the scoring in a 2-2 draw against Hajduk Split in their first European game.
Cristea played ten times for the Romanian national team from 2003 to 2010.As of match played 20 September 2017.
Statistics accurate as of match played 29 December 2012Steaua Bucureşti
Romanian League: 2004–05, 2005–06
Romanian Supercup: 2012
Serie C: 2014–15
Liga 1 Golden Boot: 2009–10