Henry Walter Maier (February 7, 1918 – July 17, 1994) was an American politician and the longest-serving mayor of Milwaukee, Wisconsin, holding office from 1960 to 1988. A Democrat, Maier was a powerful but controversial figure, presiding over an era of economic and political turbulence for the city of Milwaukee.
Maier was born Henry Walter David Nelke in Dayton, Ohio. After his father died, he moved with his mother to Springfield, Ohio to live with his grandparents. He graduated from Springfield High School in 1936. When his mother moved to Milwaukee and married contractor Charles Maier, Nelke accompanied her. He changed his name to Henry Walter Maier in 1938.
Maier served in the United States Navy during World War II. He earned a bachelor's degree from the University of Wisconsin–Madison and a master's degree from University of Wisconsin–Milwaukee. Maier was in the insurance business and taught workers' compensation and general liability insurance at the University of Wisconsin–Milwaukee.
A member of the Democratic Party, Maier was elected to the Wisconsin State Senate in 1950. In 1960 he was elected Milwaukee's mayor, succeeding Frank Zeidler, the last of Milwaukee's Socialist mayors. Maier remained in office for 28 years, succeeded by John Norquist in 1988. He was the longest serving mayor in Milwaukee history.