Martel attended the Performing Arts High School in New York, on which the movie Fame was based, graduating in 1953. She later studied method acting and was a member of The Actors Studio.

The daughter of Austrian Jewish immigrants, Martel was billed as "Arline Sax" during the early years of her television career. One of her earliest appearances was in the December 25, 1959 Twilight Zone episode "What You Need" as a girl in the bar (speaking role). She appeared in a 1960 episode of The Rebel entitled "The Hunted" in which she had a scene with Leonard Nimoy, before Star Trek. She was also featured in two 1961 episodes of Route 66: "Legacy for Lucia", in which she had the title role of a Sicilian girl who inherits an American soldier's estate, and "The Newborn," in which she played a mother who dies in childbirth. She appeared in an episode of the TV series Hong Kong in 1961, opposite Rod Taylor.

In 1962, she made the first of two appearances on Perry Mason, as Fiona Cregan in "The Case of the Absent Artist." Later, she guest starred as Sandra Dunkel in "The Case of the Dead Ringer" (1966), in which, aside from his role as Mason, Raymond Burr played the actual murderer, Grimes. Martel appeared in the Star Trek episode "Amok Time" (1967) as T'Pring, Mr. Spock's wife, and the original The Outer Limits episode "Demon with a Glass Hand" (1964).

Martel had roles in such films as Angels from Hell (1968) and Chatterbox (1977). She appeared as a featured Actress in the Gunsmoke episode titled "The Squaw" (1975). In 1974, Martel also appeared as "Tasha Martelle," playing secretary "Marty Bach" (eventual mistaken murder victim) in an episode of The Rockford Files (season 4), Episode 2, titled "Trouble in Chapter 17." She received top billing as the commandant in charge of a Russian road crew in Zoltan, Hound of Dracula (1978), although it was only a bit part lasting less than five minutes. She appeared in the Star Trek webisode "Of Gods and Men" in the final scene as a Vulcan priestess initiating a marriage ceremony between Uhura and Vulcan native Stonn (a character from the episode "Amok Time," played by original actor Lawrence Montaigne). Martel played Gloria, mistress of murder victim Tony Goodland (Bradford Dillman), in the Columbo episode "The Greenhouse Jungle" (1972).

She was a regular at Star Trek conventions worldwide from 1972 to 2014. Her last convention appearance was at TrekTrax Atlanta (later renamed Treklanta) in Atlanta, Georgia on April 25–27, 2014 – four months before her death.

Martel semi-retired from acting in the mid 1980s, but continued to work sporadically in acting after that. She appeared in several episodes of TV and in some unreleased TV pilots in the early 2000s. She stated in interviews that even in her early career, she got most of her work through word of mouth and not through talent agents. In her later years, she often remarked, "I don't have a good agent who will get me the plum roles."

Martel played the Princess Sarafina on Have Gun – Will Travel, the evil witch Malvina on Bewitched, the French Underground contact Tiger in five episodes of Hogan's Heroes (1965-71), a female cosmonaut on I Dream of Jeannie, a Hungarian immigrant Magda on The Fugitive episode "The Blessings of Liberty" (1966) and, memorably, the nurse who repeatedly utters the sinister phrase "Room for one more, Honey!" at the entrance to a hospital Morgue and the stewardess at the door of a doomed airplane in the Twilight Zone episode "Twenty-Two" (1959).

On August 12, 2014, Martel died from heart bypass surgical complications at a hospital in Santa Monica, California. She was 78 years old. She had been battling breast cancer for the last five years of her life, although this was reportedly not the cause of her death. She was survived by her children and two of her three grandchildren.

Before her death, Martel was one of the narrators for the 2015 documentary film Unity, which was released on August 12.