Mary Jane Croft was born in 1916 in Muncie, Indiana.  Her career began while she was still a teenager, on the stage at the Muncie Civic Theatre.  She then joined the Guild Theatre Company in Cincinnati, going from there to WLW, a radio station/production company that produced many radio programs.  She had radio roles in many productions including The Adventures of Sam Spade, Blondie, The Mel Blanc Show and Our Miss Brooks.

While with the radio station, she met and married Jack Zoller and the pair moved to Los Angeles in 1939.  Despite her extremely busy schedule with radio and later television, she too time off to have a son, Eric, in 1944.

As radio was brushed aside for the new medium of television, Mary Jane made the transition with ease.  She was a guest star in many television shows as well as having a regular role on Our Miss Brooks when it crossed over to television and also as the talkative neighbor, Clara Randolph, on The Adventures of Ozzie and Harriet.  

Our Miss Brooks was produced for television by a newly formed production company, Desilu Productions owned by Lucille Ball and her Cuban bandleader husband, Desi Arnaz.  The company's first show, I Love Lucy, was America's most popular television series at the time and Mary Jane made her first guest appearance on the show in 1954.  She played an old friend of Luci's from high school, Cynthia Harcourt. Mary Jane was to play Luci's friend many more times throughout all the various sitcoms she produced and starred in.

Mary Jane's personal life took a beating during the early fifties as her marriage to Jack Zoller fell apart and two ended up divorcing.  By the late fifties, however, she began dating an old friend from the radio days, Elliot Lewis.  He was divorced, also, and the two found themselves to have much in common.  They married in 1960 and were together until Lewis passed way in 1991.  Their marriage was considered by many to be one of the happiest ones in show business.  This is probably what helped her through the pain of losing her only son when he was killed in the Vietnam War.

Despite ten years playing in The Adventures of Ozzie and Harriet, Mary Jane's longest running role, she is still remembered best for being one of Luci's best friends throughout the 60s.  She played neighbor, Betty Ramsey the last season of I Love Lucy but really came into her own as a comedic foil to Lucille Ball's wackiness in The Lucy Show-with Vivian Vance, Lucille Ball, Mary Jane Crof-.  Mary Jane played two different characters in that series, actually.  During the first half of the show's run, she played Luci and Viv's friend but when the format changed after Vivian Vance left the show in 1965, Mary Jane was brought back as Mary Jane Lewis, Luci's rather ditzy next-door neighbor in California.  She continued as Mary Jane in Lucille Ball's next show, Here's Lucy, and played in that role until the show ended in 1974.

Mary Jane continued to act after Here's Lucy, however she didn't have any further outstanding roles and played mostly guest spots.  When her beloved husband died in 1991, Mary Jane finally retired from show business and lived a quiet life until she herself passed away in 1999.