Tengroth debuted in Sven Jerring's radio show 'Barnens Brevlåda' together with her friend Sickan Carlsson at the age of 10.

She got a contract with the leading Swedish studio Svensk Filmindustri (SF) in 1932 and remained there throughout the decade.

She was known for playing fresh, girl next door roles, which gave her a popular following amongst young fans.

When Ingrid Bergman made her screen debut, she was unfavourably compared to Tengroth.

She was briefly married to the Danish politician Jens Otto Krag, later Prime Minister, in the early 1950s.