In 1960, Andersen ran for governor, winning by more than 20,000 votes. During his term, the common loon became the Minnesota state bird, several state parks were established, the Taconite Amendment was passed, as was fair housing legislation. He lost his reelection bid two years later, by the closest margin ever in United States history. The election was held on November 6, 1962, but the results were not known until March 21, 1963. After recounts and court challenges, it was determined that then-Lieutenant Governor Karl Rolvaag had defeated Andersen by 91 votes out of nearly 1.3 million cast. Rolvaag collected 619,842 votes to Andersen's 619,751.