[9] In the same year, he played for the gold medal-winning Russian team in the World Youth U-16 Chess Olympiad in Kocaeli, Turkey.

[10] In 2012, Fedoseev tied for first place with Alexei Shirov in the Paul Keres Memorial rapid tournament in Tallinn, finishing second after playoffs.

[12][13][14] Fedoseev won the bronze medal at the 2014 European Individual Chess Championship in Yerevan, therefore qualifying for the 2015 FIDE World Cup.

[15] Later that year, he finished third in the "Lake Sevan" round-robin tournament in Martuni, Armenia[16] and in the World Junior Chess Championship.

[27] In June 2017, Fedoseev tied for first place with Maxim Matlakov and Baadur Jobava in the European Individual Championship in Minsk and took the bronze medal on tiebreak.

[29] In September, he reached the quarterfinals of the World Cup in Tbilisi, after knocking out Yusnel Bacallao Alonso, Ernesto Inarkiev, Hikaru Nakamura and Maxim Rodshtein.