The Junior College was established in 1962 with the goal of serving students interested in 2-years degree programs, or who would later transfer into the university's existing 4-year degree programs. The Junior College did not have its own faculty at first, but drew upon faculty from the other colleges of St. John's University. Growing interest in additional 4-year professional degrees led to several transformations and expansions of this college, soon becoming the School of General Studies in 1968, the College of General Studies in 1971, St. Vincent's College in 1972, the College of Professional Studies in 1999, and the Leslie H. and William L. Collins College of Professional Studies in 2019.
In 1968, students at the Schermerhorn Street, Brooklyn campus formed the Experimental College. It was not an official academic unit, but rather, it existed independently of the University and the Student Government. Its aim was to have “students taking responsibility for their own education and developing courses which are of interest to them,” going beyond the course requirements of a traditional degree program. The courses were non-credit, and formed by students who found a professor willing to teach it. Lasting several years, many students and faculty eagerly participated in this unique “college.”
In 1971, St. John’s University acquired the former Notre Dame College of Staten Island. It became the newest campus of the university, under a separate academic unit called Notre Dame College of St. John’s University. Students from the recently closed Schermerhorn Street campus moved to either the Queens or the new Staten Island campus. This college later merged with St. John’s College of Liberal Arts and Sciences during the 1998-1999 academic year.
In 1995, St. John’s formed a new college, the ninth academic unit active at the time, called Metropolitan College. Its focus was continuing education for adults, particularly at convenient evening and weekend times for working students. Both credit and non-credit options were available, as well as some degree programs such as a Bachelor in Liberal Studies, a Bachelor of Business Studies, and a Master of Liberal Arts. Metropolitan College continued in that format for a number of years, eventually dispersing courses into other colleges and continuing education programs at St. John’s University.
In 2001, the former College of Insurance (TCI) merged with St. John's University. It was not a separate college unit, but became the School of Risk Management, Insurance, and Actuarial Science under the Tobin College of Business. The acquisition of the College of Insurance also brought the first Manhattan campus location to St. John’s University, as TCI was housed in a building on Murray Street in lower Manhattan.