Walter Freeman was born in Washington, DC. His father was the lobotomist Walter Jackson Freeman II; his great-grandfather was William Williams Keen, the first brain surgeon in the United States.

Freeman studied physics and mathematics at the Massachusetts Institute of Technology, electronics in the Navy in World War II, philosophy at the University of Chicago, medicine at Yale University, internal medicine at Johns Hopkins, and neuropsychiatry at University of California, Los Angeles. He received his M.D. cum laude in 1954, the Bennett Award from the Society of Biological Psychiatry in 1964, a Guggenheim Fellowship in 1965, the MERIT Award from NIMH in 1990, and the Pioneer Award from the Neural Networks Council of the IEEE in 1992.[citation needed] He was a Professor Emeritus of Neurobiology, University of California Berkeley.

Freeman was President of the International Neural Network Society in 1994, and is a Life Fellow of the IEEE. He has authored over 450 articles and 4 books.

In 2008, Freeman proposed that Thomism is the philosophical system explaining cognition that is most compatible with neurodynamics.

Freeman died at his home in Berkeley, California on April 24, 2016 from pulmonary fibrosis, aged 89.