Kelsch was regarded as a top-level semi-pro player for more than a decade prior to his belated arrival in the NFL at the age of 36, appearing as a member of a variety of teams in the Pittsburgh area.[5] His path would cross with a Duquesne University Prep football player named Art Rooney in the fall of 1920 when both became members of the Northside Commercials team.His big right leg would move with the slow rhythm of a grandfather's clock, there would be a thud as his heavy cleated foot would come in contact with the ball — and over the crossbar the pigskin would soar for three points or one, as the case may be.Off the field, Kelsch was a committed bachelor, characterized in one news account as a "night-clubber, man-about-town, a member of some of the liveliest gangs that ever held sway on the other side of the Allegheny.[1] Kelsch was eulogized in the Pittsburgh Press as a gritty, working class hero: "In a city where college football is paramount, old Mose won his name.