Born and raised in Stockholm, Bäckvall started to play football with local club Sandsborgs IF as a youngster.

Bäckvall played four league games throughout the season, as Hammarby suffered a relegation, and scored a brace in a 7–1 home win against Gårda BK on 2 June 1940, making him one of the youngest ever goalscorers in Allsvenskan, at age 17.

[5] In 1950–51, the club suffered a relegation from the top division for the first time in its history, but Bäckvall decided to stay with AIK and won an immediate promotion the next season.

[3] He decided to retire from top-level football in 1953, after seven full seasons with the club, due to an injured achilles tendon.

He was a player-coach during his first two seasons in charge, making a comeback to the pitch after three years, before working as a full time manager.