Allen was born in 1882 in a log cabin in Winn Parish to Asa Levi Allen and the former Sophronia Perkins. He attended Winn Parish schools, the Springfield Normal School and Business College in Springfield, Missouri, and Trinity University, a private institution then in Waxahachie, Texas, south of Dallas in Ellis County, Texas Allen taught school in Winn Parish in 1898 and later in Mineral Springs, Texas, and Pleasant Hill in Sabine Parish. In 1908, he was an assistant registrar at Trinity. Thereafter, he worked at times in farming, railroads, the mercantile business, and in oil drilling. Allen married the former Florence Scott Love of Paris, Texas, the seat of Lamar County, Texas, on December 4, 1912. They had three children: Joyce Love Allen, Oscar Kelly Allen, Jr., and Asa Benton Allen.
Allen took an early, active interest in politics and civic affairs. After joining the Democratic Party, he was elected tax assessor in Winn Parish and served from 1916-1920. He was the clerk of the Winn Parish Police Jury from 1924-1927. He was elected to the Louisiana state Senate in 1928 in the wake of Huey Long's landslide victory in the gubernatorial election. He defeated the anti-Long incumbent, former Republican Henry E. Hardtner of La Salle Parish. Allen served was Long's floor leader in the Senate; he was also appointed by the governor as chairman of the Louisiana Highway Commission, serving from 1928 until 1930. His appointment was legally challenged. In the litigation that reached the Louisiana Supreme Court, it ruled that holding both legislative and executive positions simultaneously was unconstitutional. Allen resigned as chairman. Allen was elected governor in the shadow of Huey Long, who had resigned after being elected as US Senator from Louisiana and relocated to Washington, D.C.. Allen was considered a stooge for former governor Long. His brother Earl Long once joked that a leaf blew into Allen's office one day and that he signed it, thinking it was legislation from Long. Elected with Allen was Huey Long's choice for lieutenant governor, John B. Fournet of Jefferson Davis Parish. Fournet defeated Long's younger brother, Earl Kemp Long, who had the support of most Long family members despite Huey's support for Fournet. Allen signed into law Louisiana's popular homestead exemption, legislation pushed to passage by State Senator W. Scott Heywood of Jennings. He had been the first to discover oil in his adopted Jeff Davis Parish.
Death and honors
Allen died in the governor's mansion of a brain hemorrhage. At the time of his death, he was the Democratic nominee for Long's vacated seat in the United States Senate. He had won the Senate nomination with an unprecedented 200,000-vote plurality, but he did not live to assume the office, which went thereafter to Speaker of the Louisiana House of Representatives Allen J. Ellender of Houma, the seat of Terrebonne Parish. Ellender held the seat until his death from coronary thrombosis on 27 July 1972. Allen had been honored by the O.K. Allen Bridge across the Red River between Alexandria and Pineville; however, the bridge was imploded on September 26, 2015, due to construction on a new bridge to be named the Curtis-Coleman Memorial Bridge. The former governor is honored, along with a predecessor, Huey P. Long, by the Huey P. Long - O. K. Allen Bridge across the Mississippi River in Baton Rouge, as well as the Long-Allen Bridge over the Red River between Shreveport and Bossier City, among others. Allen Hall on the Louisiana State University Campus, is named in his honor. O.K. Allen Hall on the University of Louisiana campus is named in his honor. Allen is the subject of the Lead Belly blues tune, "Governor OK Allen Blues". His younger brother, Asa Leonard Allen, represented the former Eighth Congressional District, based in central Louisiana, in the United States House of Representatives from 1937-1953. In 1993, Allen was posthumously inducted into the Louisiana Political Museum and Hall of Fame in Winnfield, along with the two Long governors, Huey and Earl.
