He was born in Laramie, the seat of Albany County in southeastern Wyoming, the son of the former Evangeline Victoria Owen and Stephen Wheeler Downey.

In 1912, Downey split Wyoming's Republican vote by heading the state's "Bull Moose" revolt in support of Theodore Roosevelt, thus leading to a Democratic victory statewide.

The EPIC platform called for state support for the creation of jobs, a massive program of public works, and an extensive system of state-sponsored pensions and radical changes in the tax structure.

[2] In 1936, the two drifted apart, as Townsend supported Union Party presidential nominee William Lemke of North Dakota, and Downey remained a Democrat committed to Franklin Delano Roosevelt.

[1] He ran as a supporter of the proposed "Ham and Eggs" government pension program and defeated incumbent Senator William Gibbs McAdoo in the Democratic primary by more than 135,000 votes.

Though he had been considered a staunch liberal, Downey as a senator became a conservative Democrat who won the support of California's major oil interests.

He took an early stand supporting a military draft but opposed the Roosevelt administration's plans to requisition industries in time of war.

During World War II, he called for the creation of a committee to investigate the status of blacks and other minorities in the armed forces and advocated a postwar United Nations, international control of atomic energy, increased veterans' benefits, and federal pay raises.

In 1950 Downey dropped out of the race, citing ill health, and threw his support in the Democratic primary behind Manchester Boddy, the conservative and wealthy publisher of the Los Angeles Daily News.

Downey also served as a lobbyist representing the city of Long Beach and the large petroleum concerns leasing its extensive waterfront.

While he was often overshadowed in state politics by Republican progressives like Hiram Johnson and Earl Warren, Downey left a significant mark because of his tireless advocacy of old-age pensions, organized labor, and racial justice.

His conservative turn after his reelection in 1944, when he increasingly represented the interests of big business, large agribusiness concerns, and the oil industry, has obscured his historical reputation as a one-time liberal and progressive force in California politics.