Sheppard never received a world title shot. He was, what in boxing it's described as a "journeyman". However, his career had many ups and downs, of which, particularly the ups, made him an interesting boxer to watch for the fans. The February 2005 issue of Ring magazine, described him as a "gatekeeper"; in other words, he was the guy who made it impossible for many important fighters of the era to fight for the world title, by beating them.
Sheppard began his career as a professional boxer on September 24, 1938, knocking out Larry White in the first round at the Madison Square Garden. His first defeat was on November 1 of that year, against Danny Peal, by decision. Sheppard would win four fights in a row, including one against Herbie Katz, who had an immediate rematch, with Sheppard's winning streak being stopped at four, when Katz beat him by decision.
Sheppard won three and had one no contest on his next four bouts, including a win over Lee Q. Murray. His no contest bout was against Elza Thompson, on April 17 of 1941, in Pittsburgh. But then, he lost again, when defeated by decision by Willie Reddish, eleven days after his fight with Thompson.
In June of that year, he beat Q. Murray, then, on August 2, he lost by decision to future Hall of Famer Jimmy Bivins. Sheppard won five of his next seven fights, until, on July 27, 1942, he lost to future world Light-Heavyweight champion Joey Maxim, by a ten round decision. He won two of his next four fights. The two fights he did not win during that span included another no-contest, that time against Hubert Hood, in six rounds.
Maxim was the world's #1 challenger at the Light Heavyweight division at the time, and he only needed one more win to earn a world title shot. Because of this, Maxim's management, thinking that Sheppard would be an easy opponent, picked him out of all the Light Heavyweight boxers of the era.
Sheppard temporarily spoiled Maxim's plans, as he knocked out Maxim in round one of their rematch, on March 10.This result was considered to be a mild surprise by Ring Magazine writers and by many boxing fans. Needing to restore his image in order to fight for the world Light Heavyweight title, Maxim and Sheppard both signed for an immediate rematch, which would be the third fight between those two boxers. Maxim prevailed that time around, by a ten round decision.
While Maxim went on and became world champion, Sheppard continued to fight anyone, anytime. Only twenty six days later, he went into the ring with a fighter who was 12-0 before their fight: Sheppard defeated Clint Conway by a ten round decision on April 26.
Sheppard won only two of his next five fights, before embarking on a seven win streak. The first three wins in that streak were first round knockouts, including one over Conway, on December 12, 1943. On January 24, 1944, he accomplished one of his career's best performances, when he beat future challenger for the world heavyweight championship Gus Dorazio by a ten round unanimous decision.
His next fourteen fights were almost all against the elite of the Light Heavyweight division: He beat Buddy Walker by a knockout in eight rounds in a rematch. Then, he beat Tony Shucco by knockout in five, before losing to Q. Murray and to future world champion Melio Bettina, both by ten round decisions. Then, he beat Alf Brown, Dan Merritt and Buddy Walker, all except Walker being outpointed. Walker was knocked out in nine rounds. Then, he was knocked out for the first time in his professional boxing career, being taken out in seven rounds by Perk Daniels on May 9, 1945. This was followed by another points loss at the hands of Jimmy Bivins, and then, he had consecutive wins over Nate Bolden, Johnny Allen and Perkins in a rematch, before facing Jersey Joe Walcott again, and Archie Moore. He dropped decisions to Walcott and Moore, but Moore would later claim that, out of the opponents he beat, Sheppard hit him the hardest.
Sheppard would fight twenty three more times, winning fourteen and losing nine. He lost another fight to Moore, but "the king of knockouts" could never knock Sheppard out, as he had to settle for a second decision victory over Sheppard. Sheppard also lost to Bivins, Q. Murray and to Rushy Payne, each of them twice by decision, during that last twenty three fight stretch. His second fight with Payne, on January 19, 1949, was his last professional boxing fight.
Sheppard compiled a record of 49 wins and 33 losses, with 2 no-contests, and 32 knockouts.