From 1922 to 1941 he was the publisher of New York Medical Week, the official publication of the New York County Medical Society.
From 1938 until 1957 he and Victor W. Knauth edited Omnibook Magazine, which published abridged versions of current best-sellers.
Geffen was also one of the founders of the Blue List, a daily paper that consisted entirely of advertising for municipal bonds that was later merged into Standard & Poor's, which was in turn acquired by McGraw-Hill.
He also founded a magazine for doctors, Medical World News, in 1961 and sold it to McGraw-Hill in 1966 for $17 million.
In 1968, at the age of 72, he resigned as a senior vice president at McGraw-Hill and became the principal owner and chairman of the publisher David McKay, Ltd. In the same year, he started another magazine, Family Health, which was later renamed to Health.
He was the brother-in-law of the writer Matthew Josephson.