Radack was born July 6, 1937, in Titusville, Pennsylvania, and moved to the Jamestown area in 1942. He attended St. Peter and Paul School from 1943 to 1953 before attending JHS from 1953 to 1955.
Swimming was first introduced at JHS by C. Richard Bower in the school year of 1954-55 and Radack became the star of that team, which had only three official meets but posted a 2-1 record. Radack's top accomplishment was breaking the 18-year-old pool record at North Tonawanda in the Section 6 Meet. He was timed in the 100-yard backstroke trials in 1:02.8 and that clocking was enough to make him the first Jamestown All-American. The next All-American to come from Jamestown was Carl Carlson in 1995. In the second meet of the year against Erie Tech, Radack broke the pool record of 1:03.1 and later in the home pool at the YMCA he tied the pool mark in the 40-yard freestyle, the 160-yard individual medley and the 100-yard backstroke.