Cadwell was born in Everett, Washington, the daughter of Vivian and Everett Emery. Her family was Baptist and ofSwedish and English descent. Linda met Bruce Lee while she was attending Garfield High School, where Bruce came to give a Kung Fu demonstration; he was attending the University of Washington at the time. Eventually, she became one of his Kung Fu students when she was attending the University of Washington as a student studying to become a teacher.

She continued to take Kung Fu lessons from him while attending college. They married on August 17, 1964. Linda was a few credits short from graduation. They had two children together, Brandon Lee and Shannon Lee. Bruce Lee had opened his own Kung Fu school at the time and was teaching wing chun. Jeet Kune Do came later. Bruce Lee died suddenly on July 20, 1973 of cerebral edema.

Linda was married to Tom Bleecker in 1988, and they divorced in 1990. She married stockbroker Bruce Cadwell in 1991 and they live in Rancho Mirage, California. In 1996, Bleecker published a book on his version of how Bruce Lee died.

Her son Brandon Lee, an actor like his father, died in a fatal shooting accident on a movie set while filming The Crow on March 31, 1993, nearly 20 years after his father's death. Brandon's fiancee, Eliza Hutton, was involved in an out-of-court settlement with the producers of The Crow in 1993, and was instrumental in having the film released in 1994.

Cadwell has continued to promote Bruce Lee's martial art Jeet Kune Do. She retired in 2001, and her daughter Shannon (who is now in charge of the Lee family estate), together with son-in-law Ian Keasler, run the Bruce Lee Foundation, a non-profit organization dedicated to teaching Bruce Lee's philosophy on martial arts and his writing on philosophy.