The man nicknamed "The Toy Bulldog" was a welterweight and middleweight champion but ultimately won the hearts of boxing fans by fearlessly taking on heavyweights and light heavyweights.
In 1922, Walker dethroned welterweight champion Jack Britton and made successful title defenses against Pete Latzo, Jimmy Jones, Lew Tendler and Bobby Barrett.
Even as a welterweight the 5-foot 7-inch Walker began thinking big. With manager Jack "Doc" Kearns handling his career, nearly any opponent at nearly any time could be produced.
In 1925, fought to a no decision with light heavyweight champion Mike McTigue in a title bout and lost a 15-round decision to middleweight king Harry Greb. The Greb fight was a thrilling affair and legend has it that the two warriors went at it again in the streets of New York City after arguing the result of the fight in a saloon.
Walker lost the welterweight crown to Latzo in 1926 but he wouldn't be without a title for long. Before the year ended, he defeated middleweight champion Tiger Flowers.
Again, he sought bigger challenges and knocked out McTigue, then an ex-champ, and decisioned future light heavyweight champion Paul Berlenbach.
In 1929, he challenged 175-pound champion Tommy Loughran but lost a 10-round split decision. By 1931, Walker was fighting heavyweights and decided to relinquish his middleweight throne after beating top big men such as Johnny Risko and Bearcat Wright. Also in '31, Walker battled future heavyweight champion Jack Sharkey to a draw.
Heavyweight contenders King Levinsky, Paulino Uzcudun and Arthur DeKuh fell victim to Walker in 1932 but former heavyweight champ Max Schmeling knocked him out in eight rounds the same year. One more try at the light heavyweight crown came in 1933 but Maxie Rosenbloom scored a decision over Walker. A year later, Walker avenged the loss to Rosenbloom in a non-title fight.
After scoring a second-round knockout over Red Bush in 1939, Walker retired.