Mihailov was born on 22 May 1964, in Sofia, People's Republic of Bulgaria, and has a twin brother named Boris.

[3] The brothers started playing hockey at age 14,[4] and learned on the outdoor Druzhba rink in Sofia.

He played the 2004–05 season with the Galaxians d'Amneville in the French Ice Hockey Federation Division 2, then returned to Bulgaria.

[2] Mihailov first represented his country on the international level with the Bulgaria men's national under-18 ice hockey team.

[4] During the European qualification portion of the 2015 IIHF Inline Hockey World Championship Division I, Mihailov was given a standing ovation and was named the event's best goaltender.

[5] Mihailov was honored by the IIHF in 2019, as a recipient of the Torriani Award to recognize his international hockey career.