[citation needed] Clayton was a Metro-Goldwyn-Mayer starlet in the early 1940s, appearing in several films, none of them particularly notable, except for an unbilled role in 1948 as a singing inmate in The Snake Pit.

Clayton can be heard on the original cast recordings of both Carousel (1945) and the 1946 Broadway revival of Kern's 1927 musical play Show Boat.

While starring in Show Boat, Clayton met Robert Lerner, an heir to the women's clothing shops bearing his name.

She produced and starred the next year in The Brown Horse, another proposed series about a woman trying to pay for her daughter's college tuition by working in a San Francisco restaurant.

The episode, written by Jean Holloway, examines how the harsh prairie causes havoc in the lives of some of the women on the wagon train.

In the 1962 episode "St. Louis Woman" on NBC's The Tall Man, Clayton performed in the role of Janet Harper, a widow engaged to Tom Davis ( Canadian-born Russ Conway), a friend of Sheriff Pat Garrett (Barry Sullivan).

While Tom is away from Lincoln, New Mexico, the setting of The Tall Man, on a cattle drive, Janet begins to show a romantic interest in Garrett.

Of note, as the Gunsmoke episode “Bentley” ends, “Chester Goode” respectfully escorts “Clara Wright” to the stage, making Jan Clayton the last actor of note (save for some unknown townspeople) to be seen on screen with Marshall Dillon’s beloved friend, as this marked actor Dennis Weaver’s final moment on the TV Western Series.

She returned to the series in 1965, playing “Mary Rice”, a mother with scurvy who sacrifices treatment in order to save her son, also ailing with the same disease, in “Gilt Guilt” (S10E31).