He was the co-founder of the insurance brokerage firm Burroughs, Marsh & McLennan in 1905, which was renamed Marsh & McLennan in 1906 after the retirement of Mr. D. W. Burroughs. McLennan served as the Chairman of the Board from 1935 until his death in 1944 in Lake Forest, Illinois.
He was a co-founder of the insurance brokerage company Burroughs, Marsh & McLennan in 1905, which was later renamed Marsh & McLennan in 1906 after Mr. D. W. Burroughs' retirement. McLennan served as the Chairman of the Board from 1935 until his death in 1944 in Lake Forest, Illinois.