After eight years in the minor leagues, Holly was acquired from the Johnstown Johnnies, where he had batted .298 in 1906 by the St. Louis Cardinals.

He played 10 games for the Cards, batting just .059, but was apparently impressive enough to be handed the starting shortstop job in 1907, replacing Forrest Crawford.

He spent the next six seasons in that league, with the Bronchos, Montreal Royals, and Toronto Maple Leafs, where he built his reputation as a top defensive shortstop.

That year, Holly joined the Pittsburgh Rebels of the upstart Federal League.

After the season, the Federal League folded, and Holly retired as an active player.