Sister Mary Joel Acerno, C.S.J., a member of the Sisters of St. Joseph, Brentwood, L.I., for 66 years, died March 21 at Maria Regina Residence, Brentwood. She was 88.

Born Eileen Lucille Acerno in Elmhurst, she attended St. Joseph’s College for Women in Clinton Hill, where she earned her bachelor’s degree in education in 1948. She entered the convent that same year. She later earned a master’s degree in mathematics from St. John’s University, Jamaica.

She taught at St. Benedict Joseph Labre School, Richmond Hill, 1950-59; served as a mathematics professor at St. Joseph’s College for Women and was an elementary school principal at St. Clare, Rosedale, 1975-78, and Holy Child Jesus, Richmond Hill, 1978-90. She returned to the classroom at Holy Family School, Flushing, 1990-96.

She earned her paralegal degree in 1996 from Queens College and was employed by a Queens law firm. She also taught part-time at St. John’s University.

She is survived by a brother, Arthur Acerno, of Rockville Centre; and a sister, Virginia Bartley, of Plandome, L.I.

In her memory a scholarship fund has been established for Catholic high school-bound eighth-grade graduates at Holy Family School, Flushing.