Ventura was born James George Janos in 1951 and grew up in Minneapolis. His father, George Janos, was a World War II veteran who grew up in the Swede Town section of Minneapolis. Ventura's father was a maintenance worker for the city of Minneapolis while Ventura was growing up. His mother, Bernice, started as a nurse in the U.S. Army, and later worked as a civilian nurse.
Ventura and his older brother, Jan, spent a lot of time around the Mississippi River as youths, fishing for carp under a bridge that spanned the river between the cities of Minneapolis and St. Paul. They often cooked their catches over bonfires along the river banks. The brothers both became captains of their Roosevelt High School swim teams—Jan in 1966, and Ventura his senior year, 1969. Ventura knew by then he wanted a professional wrestling career.
Dinner conversations at the Janos family table may have sparked Ventura's interest in politics; his father would complain bitterly about establishment politics, calling then-presidential candidate Richard Nixon a tailless rat, according to Jan, who spoke with reporters about Ventura's political origins.