[2] In 1922, he moved to the University of California at Los Angeles (UCLA), serving as the first chair of the Department of Zoology.

[2][4] In 1947, Allen retired from the Department of Zoology, but remained at the university for 11 years as a member of the Atomic Energy Project at UCLA.

[2] He retired from that project in 1958, but remained at UCLA associated with the Department of Radiology in the School of Medicine until his death in 1963.

[2] Throughout his career, Bennet's research focused on the role of endocrine glands in development.

[2] Later in his career, upon moving to the Atomic Energy Project, Bennet's shifted his research to the effects of radiation exposure on various tissues.