Born in Blue Bell, Pennsylvania, Hollenback attended Phillipsburg High School. As an undergraduate at the University of Pennsylvania from 1904 to 1908, he became one of the school's most renowned football players. He played end in 1904. He was unable to play during the 1905 season due to a broken leg. After returning from the injury, Hollenback was moved to the fullback, a position he played from 1906 to 1908. He was selected as an All-American fullback in each of those years. As a senior in 1908, Holleback was the captain of the undefeated Penn team that was named national champion. Jim Thorpe, whose Carlisle Indians team played Penn to a 6–6 tie in 1908, called Hollenback his "greatest and toughest opponent." In 1921, Hollenback played professional football for the Union Quakers of Phila