American United Life dated from 1877. In November of that year the Knights of Pythias lodge, which had its national headquarters in Indianapolis, created an insurance program called an endowment rank for its members as a way to attract new members to the lodge.
In 1930, the lodge separated its insurance program from the fraternal order, creating United Mutual Life Insurance Company. In 1936, United Mutual merged with American Central Life Insurance Company, another Indianapolis insurer, which had been founded in 1899. The newly merged company took the name American United Life Insurance Company. After the merger, American United Life, or AUL as it is frequently called, took over the old American Central offices at Fall Creek Parkway and Meridian Street. American Central Life had constructed the building, a copy of the royal palace in Oslo, Norway, in 1930.
In December 1979, construction began on the AUL tower that helped alter the city’s skyline. In October 1982, AUL moved into its new home office, the, in downtown Indianapolis, at the time the tallest building in Indiana, at 200 North Illinois Street. One feature of the Fall Creek building since 1959 had been a signboard at the intersection of Meridian Street and Fall Creek that displayed quips and puns. That tradition continued at the downtown tower location.
As of early 1993, the Indianapolis office was staffed by some 900 employees and held $5 billion in assets at the end of 1992. In 2000, the company converted to a mutual insurance holding company after lobbying for a change in Indiana law. OneAmerica Financial Partners was formed, with AUL, State Life, and Pioneer as subsidiaries. The OneAmerica logo was placed on the upper northwest face of the tower in 2002. In 2020, the company employed 9,875, 1,000 of them in Indianapolis.