Her father, from a junior branch of a family of minor Yorkshire gentry resident at Kilnsey,[3] was a producer and talent agent for MCA;[1] her mother was a Russian prima ballerina who appeared with the Ballet Russe de Monte Carlo.

Tennant's maternal grandfather, Mikhail Baronov, was a senior officer in the Imperial Russian Navy; his wife, the former Lydia Vishniakova, was a general's daughter.

After a number of roles in British and other European films, including The Ragman's Daughter (1972) and Inseminoid (1981), Tennant emigrated to the United States.

In 1987, Tennant starred in the neo-noir crime thriller Best Seller and the psychological drama film Flowers in the Attic playing the leading role.

[7] The following years, Tennant appeared mostly in the smaller-scale films and guest-starred in the television series including Diagnosis: Murder, JAG, Scrubs and Monk.