He played his first match for the senior team of SK Slavia Prague in September 2006, when he was just 17 years old. A month later, he scored his first league goal.
In 2007–2008 season, he made his debut in the UEFA Champions League, however, he was loaned to FK Jablonec 97 for the second half of the season. Despite playing only 14 matches (of 30), he was Jablonec's top scorer of the season with five goals. When Necid came to FK Jablonec 97 they were at the 15th place (out of 16), which means relegation to a lower league. Nevertheless, the team finished the season at the 12th place, and therefore survived, with Necid being one of the heroes of the team. When his loan came to an end, he stated he wanted to return to Slavia and did not want to play for Jablonec again.
In August 2008 PFC CSKA Moscow, who were interested in Necid since 2006, signed a deal with Slavia Prague according to which Necid would stay at Slavia until the end of the year and would join CSKA in January 2009. He played his first competitive match for CSKA Moscow on 7 March 2009 in the Russian Super Cup 2009 where he came on as a substitute on the 78th minute and scored the winning goal for his team in extra time in the 113th minute. Before joining PFC CSKA Moscow Necid played 16 games in the 2008–09 Gambrinus liga and scored 11 goals (which was making him the season's top league scorer at the time he left).
In his debut match for CSKA at the 2009 Russian Super Cup, Necid came on as a substitute when the score was 1–1 and scored the winning goal.
Necid signed for PAOK for the 2013-2014 season with Olympiacos, Rennes and FC Twente all interested. Necid had suffered an injury the season before and chose PAOK to gain more playing time.
On 6 January 2014, Slavia Prague announced signing Necid on loan to the end of 2013-2014 season. In August 2014, he was sent on loan to Dutch Eredivisie side PEC Zwolle. His loan ended in January 2015 and he returned to CSKA. After being linked with Chievo Verona, Necid dissolved his contract with CSKA on 2 February 2015. He returned to PEC Zwolle as a free agent and signed a contract until the end of the season.
His first match with the senior team took place in 19 November 2008, in a qualification match against San Marino. The Czech national football team won 3–0, with Necid scoring the third goal. After that, Necid scored three goals in World Cup qualification. He scored his fifth goal in a 4–2 win over the USA in an international friendly on 25 May 2010. His sixth was scored in a 4–1 win over Latvia.