Born Betty Kay Ageloff in New York City, Aberlin had a regular role on the children's television series Mister Rogers' Neighborhood. She also appeared on The Smothers Brothers Show (1975) and various TV spots. Later in her career, she formed a friendship with Kevin Smith (who has called her "the biggest heart on the planet") and became a frequent collaborator, appearing in Dogma, Jersey Girl, Zack and Miri Make a Porno and Red State. She had a supporting role as "Cheryl" in the Joseph Papp production of Cryer & Ford's "I'm Getting My Act Together and Taking it on the Road" at The New York Shakespeare Festival's Public Theatre in New York.
As a contributor to the literary website "Fresh Yarn," Aberlin's essay, The Blonding of America, was published in 2005. She has also published a collection of poems, The White Pages Poems, as a companion to A Book of Strife, in the Form of the Diary of an Old Soul, an 1880 collection of poems by George MacDonald.