He was involved in business ventures including fruit growing, oil refining, and lumber, partly thanks to his inheritance. In 1900, together with Burton E. Green, Charles A. Canfield, Max Whittier, William F. Herrin, Henry E. Huntington, William G. Kerckhoff, W.S. Porter and Frank H. Balch, known as the Amalgated Oil Company, he purchased Rancho Rodeo de las Aguas from Henry Hammel and Andrew H. Denker and renamed it Morocco Junction. After drilling for oil and only finding water, they reorganized their business into the Rodeo Land and Water Company to develop a new residential town later known as Beverly Hills, California. Addendum: This purchase could not have been made by 13 year old Frank H. Buck Jr. It must refer to Frank H. Buck Sr, his father. Frank H. Buck married Anna Stevenson in 1886, and their first son, Frank H Buck Jr was born the following year. Frank H. Buck was the son of Leonard W Buck and Anna Bellows Buck. He became the leader of the newly founded California Grower's and Shipper's Protective League, a lobbying organization to protect the rights of fruit and vegetable growers. In 1933, he sold the Buck Company, his grandfather's company, to the Pacific Fruit Exchange.
Politics
He served as delegate to the Democratic National Conventions in 1928, 1936, and 1940. In 1932, he was elected as a Democrat to the U.S. House of Representatives. He served in Congress from March 4, 1933 until his death in Washington, D.C. on September 17, 1942. He is credited with naming the Social Security program.
Personal life
He married Zayda Zabriskie in 1911 and they had four children, Frank Henry Buck III, Margaret Ann Buck, Christian Brevoort Zabriskie Buck and Edward Zabriskie Elvis Buck. After they divorced, he married Eva Mathilde Benson in 1926, and they had two children, William Benson Buck and Carol Franz Buck. He died on September 17, 1942, while still in office. He was interred in Vacaville-Elmira Cemetery, in Vacaville, California. His wife, Eva Benson Buck, founded the Frank H. Buck Scholarship, which is awarded each year to eight to 16 high school seniors, who have to live in his former congressional district. She was an active philanthropist until her death in 1990.