Malgosia Tomassi was born in Warsaw, Poland. Tomassi presently works as an interior designer. She is the wife of actor Stacy Keach, whom she met on the set of Mickey Spillane's Mike Hammer. She has performed alongside her husband in various Mike Hammer-related television shows, including Mickey Spillane's Mike Hammer, The New Mike Hammer and, most recently, Mike Hammer, Private Eye as the yoga instructor Maya Ricci.

Tomassi is a former European fashion model and American actress.