It was founded in 1938 as a law school by Florentino Cayco Sr., the first Filipino Undersecretary of Public Instruction.

[3] The university was named after Cayetano Arellano, the first Chief Justice of the Supreme Court of the Philippines.

It was relocated back to its old site in Legarda when a new modern four-storey concrete building was erected in 1955.

[2][8] Later on, the university began to fully integrate the K-12 program with the offering of Senior High School (SHS) strands.

It is one of the oldest law schools in the Philippines and rose to prominence by producing successful graduates who mold the political history of the country.

The College of Criminal Justice Education offers a four-year course leading to a degree of bachelor of science in criminology.

Arellano is one of the member higher educational institutions of the joint De La Salle University-CHED Zonal Research Center.

[12] AU has several academic partners that aim to facilitate collaborations in teaching, research, joint study programs, staff and student exchange, professional certification, and continuing education.

AU's seal was prepared by National Artist Vicente Manansala and was heavily inspired by a World War II photograph of American marines raising the Flag of the United States on the summit of Mount Suribachi.

Persons affiliated to the university, either as students, faculty members, or administrators, are known as "Arellianites" and/or "Arellanistas".

Throughout the university's history, faculty, alumni, and students have played prominent roles in many different fields.

Prominent alumni of Arellano in the film and media industry include Jhong Hilario, Bayani Agbayani, Joey de Leon, and Ted Failon.