Another one-time senator, Tom Daschle, told the crowd in Sioux Falls the working people and small farmers of South Dakota had a champion in McGovern, who was the Democratic presidential nominee in 1972.
"His constituents were the people for whom he fought," said Daschle.
McGovern spent three terms in the Senate and was best known for his liberal, anti-war presidential campaign in 1972 that ended with a landslide loss to Richard Nixon.
McGovern was eulogized Friday for his lifetime body of work rather than his presidential defeat, the Sioux Falls Argus-Leader said.
"When a hungry child needed a voice, he was there. When women and young people sought to break down the closed political system, he was there," said former Sen. Gary Hart, who was one of McGovern campaign organizers in 1972.
Some South Dakota residents echoed those sentiments after the service.
"The cause of peace and justice for all radiates no matter what your politics are," Patti Roberts told KELO-TV, Sioux Falls.
McGovern died Oct. 21 at age 90.