Branden was born with the name Nathan Blumenthal in Brampton, Ontario, Canada.
He met Ayn Rand in 1951, having previously read and admired her novel The Fountainhead, and the pair went on to have many discussions about Rand's Objectivist philosophy. They had an affair, despite both being married (with the full knowledge and approval of both spouses). Branden has written an account of this time, entitled My Years with Ayn Rand (1999).
Branden's major field in psychology is self-esteem, on which subject he has written books and presented seminars[1]. He lives in Los Angeles, California.