Born in Moscow of Volga Tatar descent, Izmailov emerged through local FC Lokomotiv Moscow's youth ranks, making a lightning progression in a period of six months. He was already a very important first-team member when Lokomotiv won the Russian Premier League titles in 2002 and 2004, and the player received the 2001 award for Best Young Player. However, early on, he also often suffered with injuries. On 24 October 2001, Izmailov was one of the players who helped crush R.S.C. Anderlecht in Brussels, for the season's UEFA Champions League.
Sporting
In July 2007, Izmailov was loaned for one season to Sporting CP, making his official debut in the Supertaça Cândido de Oliveira on 11 August, against FC Porto in Leiria. The game ended 1–0, with the game's only goal being scored by him at the 75th minute, with a long-distance effort; he also played that match with an injury. On 6 October 2007, coming from the bench, Izmailov contributed with two late goals in a 3–0 home win against Vitória de Guimarães, and eventually helped the side finish second in the Primeira Liga, adding the Taça de Portugal also against Porto. During the following summer he signed a permanent deal with the Lisbon-based club, which paid Lokomotiv €4.5 million. In 2009–10, Izmailov's physical problems resurfaced, and he would spend more than three months in the sidelines with a knee condition. He returned to training following coach Paulo Bento's dismissal, in late November 2009, but spent most of the following years on the sidelines nursing the same injury, and quarreling with Sporting's board of directors over the issue.
Porto
On 7 January 2013, after passing the pertinent medicals, Izmailov joined Porto on a two-and-a-half-year contract, with Miguel Lopesmoving in the opposite direction. He changed his jersey name from Izmailov to Izmaylov, and scored in only his second match, helping to a 2–0 home win over F.C. Paços de Ferreira. On 31 January 2014, after spending four months in his country due to family reasons, Izmailov signed for Gabala FK in the Azerbaijan Premier Leagueon loan until the end of the season, rejoining former Lokomotiv coach Yuri Semin who he worked with nine years ago. On 16 July he returned to his homeland and signed on loan for FC Krasnodar, which had the option of making the move permanent at the end of the campaign. Izmailov scored his first goal in Russian football in seven years on 14 August 2014, netting his team's first in a 4–0 home win against FC Spartak Moscow. He left Porto at the end of his contract, in July 2015.
Krasnodar
On 20 July 2016, after one year out of football, 33-year-old Izmailov signed a one-year contract with Krasnodar with an extension option. On 15 March 2017, he and club parted ways by mutual consent.
Izmailov made his debut with Russia aged just 19, and was summoned for the squads at the 2002 FIFA World Cup and UEFA Euro 2004, playing twice in each of those tournaments. On 25 May 2012, after an absence of six years, he was selected by manager Dick Advocaat for his Euro 2012 squad.
