Sewell was selected four times to the National League All-Star team (1943–1946) and is credited with inventing the "Eephus pitch."

Born in Decatur, Alabama, Sewell attended Vanderbilt University in the 1930–31 school year, where he played college football on scholarship for coach Dan McGugin.

The fight was eventually broken up by the police, and the next day, Sewell was called in by manager Mickey Cochrane, who told him: "Rip, don't think I feel any less about you for it; in fact, I think more of you, but we've got thirty pitchers and only one first baseman.

According to Auker, Greenberg "slapped Sewell across the face and pretty near busted his skin open.

The first time Sewell threw the blooper in a game was in an exhibition match against the Detroit Tigers.

With the American League ahead 8–0, Williams came to bat, and Sewell nodded, indicating the blooper was coming.

Williams laughed, the fans loved it, and Sewell received a standing ovation when he walked off the mound.

[7] Sewell was a critic of the American Baseball Guild, the players' union that attempted to organize after World War II.