Sister Joanne Callahan is an Ursuline Sister of Tildonk. She received her BA in Mathematics and her Master's Degree in School Counseling from St. John's University. She was an elementary and high school teacher, high school Guidance Counselor and Principal before joining the Education Department of the Diocese of Rockville Centre. She became the Director of Teacher Personnel in 1988, the Director of Regional School Planning in 1990, and is the Superintendent since 1993. In 2001 Bishop Murphy appointed her to be Secretary of Education and Formation as well.

Sister Joanne is a member of New York State Commissioner of Education's Nonpublic School Advisory Committee. In 1998, Sister Joanne received the Distinguished Alumnae Award from St. John's University.