She made her screen debut as Kumiko in The Karate Kid Part II (1986) and reprised the character for the streaming series Cobra Kai (2021).

[9] In 1993, she co-starred opposite Ming-Na Wen in the ensemble cast drama The Joy Luck Club and the next year she had a role in the 1994 independent film Picture Bride.

[10] In the 21st century, Tomita has had roles in other independent films and co-starred in several major Hollywood productions, including playing Janet Tokada in The Day After Tomorrow.

She was also in Only the Brave about the Japanese American segregated fighting unit, the 442nd Regimental Combat Team of World War II, which included two other Karate Kid stars, Yuji Okumoto and Pat Morita.

She had longer term recurring roles on Crossing Jordan, JAG, 24, Eureka, Heroes, Law & Order: Los Angeles, Glee, Teen Wolf, Resurrection, How to Get Away with Murder, and Chasing Life.

[14] Tomita began a recurring role as the Vulcan/Romulan hybrid Commodore Oh on the CBS All Access web television series Star Trek: Picard in 2020.

After her first marriage ended in divorce, she started a long-term relationship with actor Daniel Blinkoff, and they had been together for 13 years as of 2017;[17] as of August 2021[update] they were married and had founded the Outside In Theatre, in the Highland Park neighborhood of Los Angeles.