Known as the Braddock Bearcat,[1] Klaus claimed the vacant World Middleweight Championship in 1913 and was elected to the Ring Boxing Hall of Fame in 1974.

[5] He began his amateur career as early as 1904, and in February 1905 had three round wins on points in Pittsburgh against Frank Walton, and James Harris.

During his career, the Pennsylvania-born middleweight fought some of the greatest welter, middle, and light heavyweights of his era, including Jack Dillon, Battling Levinsky, Mike Gibbons, Harry Greb, and Al McCoy.

His victories over Jack Dillon, and later fellow claimant Georges Carpentier and former champion Billy Papke in France, cemented his claim to the title.

[8] On September 9, 1912, Klaus defeated Marcel Moreau in Savoie, France as the result of a low blow foul in the fourth of fifteen rounds.

[9] In another important win that cemented his claim to the title, Klaus defeated contender Eddie McGoorty on May 24, 1913, in a six-round bout in Pittsburgh.

The extra weight Klaus was carrying in his midsection led many reporters to believe he had not trained adequately for the bout, and had underestimated the ability of his opponent.

In the fifth round of six, the referee stopped the fight resulting in a technical knockout after Chip knocked Klaus to the mat for a second time.

[3] In what most considered a decisive win, the Scranton Truth wrote that Chip was the master of Klaus in every way, and clearly deserved the title he had taken from him two months earlier.