Samms originally had her sights set on a career as a ballet dancer, and, at age 10, was already studying with and doing arabesques for the Royal Ballet Theatre in London. A bout with bursitis ended all hopes for her dance career and, after a brief stint studying to be a medical technician, Samms became a model, signed by a Japanese cosmetics company. Tiring of modeling, she won the role of Princess Zuleira in a 1978 feature film version of "Arabian Adventure" on her first audition. The miniseries "Goliath Awaits", in which she was opposite Mark Harmon, followed, and Samms decided that to find true stardom as an actress, she'd have to give Hollywood a go. She did, and in 1982 joined the cast of "General Hospital" as Holly Scorpio, at the time one of the hottest role in daytime TV. Samms stayed for three years, long enough to become a frequent subject of tabloid articles and gossip columns, and then moved to ABC primetime replacing Pamela Sue Martin as Fallon Carrington Colby, daughter of Blake and Alexis and wife of Jeff, on "Dynasty". Soon after she arrived, the character was key to the 1985-87 spin-off, "The Colbys". Samms then went back to Denver and "Dynasty" until it was canceled in 1989.

By that time, Samms was already appearing in TV longforms. She was Violet Weiler in the 1984 CBS miniseries "Ellis Island" and also co-starred in the TV-movie "Murder in Three Acts" (CBS, 1986). A decade later, she broke ground at the Sci-Fi Channel, appearing in one of the network's first original movies, "StarQuest", as a government agent with a decidedly cold approach. In 1995, Aaron Spelling, Samms' "Dynasty" boss, tapped her to play the vixen role in the struggling Fox series "Models, Inc." in an effort to save the show, but it didn't work.

Samms has also appeared in a few feature films during the 90s, including "The Shrimp on the Barbie" as leading lady to Cheech Marin, "Delirious" (1991) as, aptly, a soap opera queen, and "Illusions" (1992), as a woman who suspects her sister of sleeping with her husband.

Samms' brother Jamie, one year her junior, died of aplastic anemia when she was about 10 years old. His death has had a profound affect on her life and in 1979 she co-founded The Starlight Foundation, an internationally known charity which grants wishes to critically and terminally ill children.