“I’d love to ascribe that scar to some great dramatic event, but actually I fell off my tricycle when I was a sprout of five.” (Source)
Clive Hirschorn provides a lengthier account in his biography of Gene Kelly:
“As a child [Gene] was singularly accident-prone, and at the age of six, while riding a tricycle without handlebars on Mellon Street [in Pittsburgh], he lurched forward on to an exposed piece of cast iron. The metal went through his cheek, causing a deep gash which bled profusely. Mrs. Kelly was out at the time, and a neighbour, hearing him cry, rushed him home, and as his wound continued to pour blood into the kitchen sink over which he was perched, she called the family doctor who stitched him up. To this day he still carries the evidence of the accident in the shape of a small, half-moon scar on the right [sic] side of his face.”
In his TCM tribute to Gene Kelly (below), Christopher Walken also references the star’s small though noticeable scar: “With his handsome face and his charismatic smile he was a natural leading man and that small scar added a rugged quality to his everyman good looks. The ladies loved him, he was charming, sure of himself.”
Finally, Kelly’s scar was even mentioned when he received the AFI Lifetime Achievement Award in 1985. Host Shirley MacLaine began by calling the little mark, “the sexiest thing I ever saw.” On a more serious note, she claimed that Kelly’s refusal to cover it up told viewers a great deal about him as an actor, dancer, and person. By turning down offers to “fix” his face, Kelly implies that actors and dancers should not lie about their performances, the emotions they are attempting to convey, or the characters they are inhabiting. After all, MacLaine concludes, Gene Kelly is not only dancing for himself and the narrative, but for each of us in the audience who dreams that one day s/he’ll also be able to dance in that manner.