After losing his first race for Nebraska's 1st Congressional District in 1962 to incumbent Ralph Beermann, Callan was narrowly elected to the Eighty-ninth United States Congress in 1964, serving from January 3, 1965, to January 3, 1967.
After losing his initial race for Nebraska's 1st Congressional District in 1962 to incumbent Ralph Beermann, Callan was narrowly elected to the Eighty-ninth United States Congress in 1964, serving from January 3, 1965, to January 3, 1967.