Hanburger was drafted by the Redskins in the 18th round of the 1965 NFL Draft. As a professional, he was considered as one of the best outside linebackers of his era and was elected to the Pro Bowl nine times during his career, the most in Washington Redskin history. Hanburger earned the nickname "The Hangman" due to his penchant for clotheslining tackles. From 1973 to 1977, he called the Redskins' defensive signals and acted as the defensive quarterback for head coach George Allen. He was a Four-time First-team All-Pro in 1972, 1973, 1975 and 1976 and a Second-team All-Pro in 1969 and 1974. Additionally, he was either a Pro Bowler or an All-Conference selection every year from 1966 though 1976 with the exception of 1971—receiving post-season honors in 10 of 11 seasons in that span. From 1971 to 1973, he and Jack Pardee, outside linebacker on the opposite side, formed a particularly effective tandem. In 1972, he was named the NFC Defensive Player of the Year by the Kansas City Committee of 101. That year, the Redskins won the NFC championship game of the 1972-73 NFL playoffs against the Dallas Cowboys, when they limited them to 3 points, 96 rushing yards, and 73 net passing yards with Roger Staubach at quarterback, Hanburger getting a sack. But, though the defense allowed only 14 points, the Redskins lost Super Bowl VII to the Miami Dolphins.