Though primarily a line-drive hitter, Heilmann could also hit for power. His 19 home runs in 1921 ranked fifth in the American League, and he ranked among the league leaders in home runs 11 times. On July 8, 1921, Heilmann hit a home run off "Bullet Joe" Bush that traveled over the center field fence in Detroit and "actually made the patrons gasp in astonishment." Heilmann's home run was widely reported to have traveled 610 feet, eclipsing Babe Ruth's longest home run of 465 feet. Detroit's grounds keeper was more conservative, reporting that no measurement was made, but estimating that it traveled more than 500 feet. In a column published after the 1921 season, Grantland Rice rated Heilmann as the premier scholar in the American League's School of Swat, ahead of Cobb and Ruth.