A truly gifted athlete, Liebler came to Holy Cross from New York with an outstanding reputation as a basketball and baseball player. In basketball at Holy Cross he was second to Tommy Heinsohn in scoring during the 1955-1956 season when the Crusaders were ranked No. 14 nationally and were selected to participate in the NCAA Tournament. As a sophomore, Liebler played on the 1954 team that won the NIT Championship.
In baseball he compiled an earned run average of 1.87 in 1955. When not pitching, he played the outfield and in 1955 led the team in hitting with a .368 average and a slugging percentage of .579. With these credentials, he was picked on the All-New England team.