|23rd Governor of Minnesota|
August 22, 1936 – January 4, 1937
|Lieutenant||William B. Richardson (acting)|
|Preceded by||Floyd B. Olson|
|Succeeded by||Elmer Austin Benson|
|28th Lieutenant Governor of Minnesota|
|Governor||Floyd B. Olson|
|Preceded by||Konrad K. Solberg|
|Succeeded by||William B. Richardson|
January 2, 1890|
|Died||March 29, 1968
Columbus, Ohio, United States
|Spouse(s)||Rigmore C. Wosgaard (1st), Medora Grandprey (2nd)|
Hjalmar Petersen was born in Eskildstrup, Denmark. His career in journalism culminated in his purchase in 1914 of the Askov American in Askov, Minnesota, a weekly newspaper he owned for the rest of his life.
After serving as Askov's village clerk and mayor, Petersen won two terms in the Minnesota House of Representatives, where he sponsored the state income-tax law and urged that tax revenues be spent on public education. Before he ran for the Minnesota Legislature he had been a member of the Republican Party. By the time he ran for office he was a member of the Farmer-Labor Party. He served in the legislature from 1931 to 1934, representing the old House District 56.
Petersen was elected the 28th Lieutenant Governor of Minnesota in 1934 and served with Governor Floyd B. Olson. He was sworn in as governor two days after Olson died of cancer on August 22, 1936. He served the remainder of Olson's term but declined to run for governor himself in the November general election, opting instead to launch a successful bid for Railroad and Warehouse Commissioner, a position he then assumed after leaving the governship on January 4, 1937. He later ran for governor in 1940 and 1942, losing both times to Harold Stassen.
After his term as governor, he served as the president of the American Publishing Company. He was married twice, first to Rigmor C. Wosgaard in 1914 and later to Medora Grandprey in 1934. He died in 1968 in Columbus, Ohio.
- Minnesota Historical Society's Governors of Minnesota (Minnesota Legislators Past and Present) 
- Minnesota Legislators Past and Present-Hjalmar Petersen
- Hjalmar Petersen,Twenty-third State Governor (Minnesota Historical Society) 
- Minnesota Governor Hjalmar Petersen (National Governors Association) 
- Keillor, Steven J. Hjalmar Petersen of Minnesota: The Politics of Provincial Independence ( Minnesota Historical Society Press. 1987)
Konrad K. Solberg
|Lieutenant Governor of Minnesota
William B. Richardson
Acting Lieutenant Governor
Floyd B. Olson
|Governor of Minnesota
Elmer Austin Benson