His 1092 walks ranked fourth in NL history when he retired, and remain a franchise record; he also hit .348 in the World Series, which he competed in four times.

His .394 career on-base percentage was the highest by a 20th-century third baseman until Wade Boggs exceeded it in the late 1980s, and was the top NL mark until 2001.

In the 1932 World Series against the New York Yankees, his sole appearance was as a pinch runner for Gabby Hartnett in the eighth inning of the final 13–6 Game 4 loss.

In 1935 he began to assume Traynor's mantle as the league's top third baseman, batting .311 and finishing third in the NL in on-base percentage and tied for fourth in steals.

He quickly became one of the sport's most popular players, and 21-year-old team employee Bill Veeck (William's son) staged a 1935 promotion in which fans were given mirrors labeled "Smile with Stan", with Hack's face on the reverse side; but the fans used the mirrors to reflect sunlight into the eyes of opposing batters, and the umpires threatened to forfeit the game if they didn't stop.

In Game 6 at Navin Field, he doubled with two out in the sixth inning, and tripled to lead off the ninth with the score tied at 3, but the Cubs were unable to drive him in.

Manager Charlie Grimm opted to let starting pitcher Larry French bat with one out, and French hit a ground ball to the pitcher, Tommy Bridges, with Augie Galan flying to left to end the inning; the Tigers won the Series in the bottom of the inning when Mickey Cochrane scored on Goose Goslin's single.

He had another outstanding campaign in 1940, topping the league in putouts (175), assists (302) and double plays (27), finishing fourth with a .317 batting average, and tying for the NL lead in hits (191).

And in 1942 he was third in hits and doubles, fourth in runs and walks, and fifth in on-base percentage, while again batting .300 and leading the NL in fielding average for the first time with a .965 mark.

1943 saw a slight drop-off in his performance, though he was still among the league leaders in walks and on-base percentage, with a .289 batting average, and was again an All-Star; but a strained relationship with manager Jimmie Wilson led Hack to retire at season's end.

But 1945 marked a full comeback as he enjoyed one of his best years, leading the NL again in putouts (195) and fielding average (.975), and setting a record with 54 consecutive error-less games.

After another walk and single, he came to bat in the 12th inning with the score tied at 7, two out and pinch runner Bill Schuster on first base; Hack doubled to left field off Tiger pitcher Dizzy Trout, with the ball taking a sharp bounce over outfielder Hank Greenberg's shoulder, giving the Cubs an 8–7 win and tying the Series.

His 1,239 runs were the third most by a third baseman, behind only Arlie Latham (1,478) and Lave Cross (1,333); his 165 stolen bases were the fourth most by any National Leaguer between 1920 and 1950, trailing only Frankie Frisch, Max Carey and Kiki Cuyler.