The New School for Social Research was founded in 1919 as an institution of higher education devoted to adult learning. As the school grew into a university, this original division was alternately known as the "Founding Division" or the "Adult Division." In 1943, the school was divided into two schools, the School of Politics, and the School of Liberal Arts and Philosophy. At this time, in response to the needs of returning veterans wishing to take advantage of the GI Bill, the school began a program called Senior Year at the New School. Geared toward adults who had previously completed some coursework, the program offered undergraduate credits for some courses and awarded bachelors' degrees. However, the majority of students continued to take non-credit courses.

Although The New School offered some undergraduate credits beginning in the 1940s, the first full-time day program was not established until 1972. Called the Freshman Year Program, it initially focused on college-level courses for high school students or recent high school graduates, who would then matriculate elsewhere. The program expanded as the Seminar College in 1977 and further grew in 1985 with a large donation and new name, Eugene Lang College.

In 1933, the New School for Social Research established the Graduate Faculty of Political and Social Science. Also known as the "University in Exile," the division was founded in order to host German and other European scholars who left their countries of origin to escape political and racial persecution. The Board of Regents of the State of New York granted a provisional charter in 1934, allowing the Graduate Faculty to confer Master of Social Science and Doctor of Social Science degrees. This was the first time the New School for Social Research offered credits leading to a degree to students in any of its programs. In 2005, the Graduate Faculty changed its name to The New School for Social Research, reclaiming the founding name of the entire institution, which had been dropped eight years before.

In 1970, Parsons School of Design became affiliated with The New School. The American artist William Merritt Chase founded the school in 1896 as the Chase School of Art. It went through several name changes (New York School of Art, New York School of Fine and Applied Art), but was connected in the public's mind to the school's charismatic president, Frank Alvah Parsons. In 1942, the Board of Trustees officially renamed the school Parsons School of Design.

In 1989, the Mannes College of Music became affiliated with the New School. The school was founded as the David Mannes Music School in 1916 by musicians and educators David Mannes and Clara Damrosch Mannes. It was originally located on Manhattan's Upper East Side, on East 70th Street. In 1938, the school changed its name to the Mannes Music School. In 1953, Mannes began offering degrees, and became the Mannes College of Music.

In 1997, the New School for Social Research was officially renamed New School University. The founding division, still devoted to adult education, was given the general name The New School, now comprising one of seven divisions of New School University. In 2005, the school underwent another series of name changes, which led to the overarching organization being called The New School, while the adult education program was named The New School for General Studies. This name was changed in 2011, when the adult education program was called The New School for Public Engagement and combined with the Milano School of International Affairs, Management, and Urban Policy, which until that time had been a separate division.

In 2015, a rebranding of the university resulted in several changes to divisions and names. As of 2018, The New School consisted of 5 divisions: The New School for Social Research; the Schools of Public Engagement (including: Bachelor's Program for Adults and Transfer Students; Creative Writing Program; Milano School of International Affairs, Management, and Urban Policy; School of Media Studies; and School of Languages); Parsons School of Design; Eugene Lang College of Liberal Arts; and College of Performing Arts (combining the Schools of Mannes, Jazz and Drama).

In 2025, the Schools of Public Engagement was eliminated.