In 1963, while working at Bell Labs, he developed the BEFLIX programming language for creating bitmap computer-produced movies.

He completed high school one year early, then entered Cornell University to study engineering physics.

"[2] In 1962, Knowlton earned his Ph.D. degree from the Department of Electrical Engineering at the Massachusetts Institute of Technology in 1962 under the supervision of Victor Yngve.

[3] In 1963, Knowlton developed the BEFLIX (Bell Flicks) programming language for bitmap computer-produced movies, created using an IBM 7094 computer and a Stromberg-Carlson 4020 microfilm recorder.

[4][5][6] In 1966, he prepared an animated film as an introduction to the Bell Telephone Laboratories' Low-Level Linked List Language (L6).

[7] In 1966, Knowlton and Leon Harmon were experimenting with photomosaics, creating large prints from collections of small symbols or images.