While raising her son, she worked from home, writing newspaper articles and short stories, before finally breaking into television[4] writing Westerns, furnishing scripts for Dick Powell's Zane Grey Theatre (1960), The Rebel (1961), Lawman (1960–62), The Tall Man (1962), The Rifleman (1960–63) and The Big Valley (1965–69) during the 1960s.
She was also responsible for three episodes of the original Star Trek series, writing "The Gamesters of Triskelion" and "The Paradise Syndrome" (both 1968), and provided the final teleplay for "The Cloud Minders" (1969).
She later wrote two episodes of Star Trek: The Animated Series ("The Lorelei Signal" and "The Ambergris Element", both 1973).
Armen also co-wrote (with Alfred Harris) "The Savage Syndrome", an episode of the cancelled series Star Trek: Phase II.
Armen ceased writing for television in 1983, publishing the western novel The Hanging of Father Miguel in 1984.