Charles Francis "Frank" Moran (18 March 1887–14 December 1967) was an American boxer and film actor who fought twice for the Heavyweight Championship of the World, and appeared in over 135 movies in a 25 year film career.

Born in Pittsburgh, Pennsylvania, Moran studied dentistry at the University of Pittsburgh where he also played football. He played professional football for the Pittsburgh Lyceums and Akron Pros as a guard and center.

While Moran was serving in the U.S. Navy in 1908, he knocked out fighter Fred Cooley in the second round. He began his career as a prize-fighter that same year with a match against Fred Broad. Soon, Moran, who had a hard right hand punch which he called "Mary Ann", became known as the "White Hope" of the teens. In 1914 he fought Jack Johnson for the Heavyweight Championship of the World, and in 1916 "The Fighting Dentist" went up against Jess Willard for the same title, but lost both bouts. He lost his last fight to Marcel Nilles for the Heavyweight Championship of France on December 22, 1922. He retired from boxing after 66 bouts with a record of 36 wins (28 by a knockout), 13 losses, 16 draws and 1 no contest.

Jess Willard (December 29, 1881 – December 15, 1968) was a world heavyweight boxing champion known as the Pottawatomie Giant.

He won the heavyweight title from Jack Johnson in April 1915 which earned him the nickname "The Great White Hope". He was known for his great strength and ability to absorb tremendous punishment, although today he is best known for his title loss to Jack Dempsey.

Willard held the championship for more than 4 years but only defended his title once as few people dared to challenge him. Today his reign is considered the 11th longest in the heavyweight division. He lost the title to Jack Dempsey in 1919 and to this day the fight is considered the worst beating any man has ever received in the history of boxing. Willard was knocked down for the first time in his career during the first round and another 6 times before the round was over; he suffered a cracked skull, broken ribs, shattered jaw, broken nose, four missing teeth, partial hearing loss in one ear along with numerous cuts and contusions. Jess fought for two more rounds before retiring on his stool due to the injuries he received in the first round, relinquishing the title. It is one of the most controversial fights in boxing history and many thought Dempsey had something in his gloves during the first round to act as a knuckleduster to weaken the big Willard down.

Jack Sharkey (October 26, 1902 – August 17, 1994) was an American heavyweight boxing champion. He was born Joseph Paul Zukauskas (his birth surname is sometimes given as Cukoschay), the son of Lithuanian immigrants, in Binghamton, New York but moved to Boston, Massachusetts as a young man. Sources report little of his early life until, at the outset of the First World War, teenaged Joseph repeatedly tried to enlist in the Navy. Turned down because of his age, he was not able to enlist until after the end of the war.

It was during his tenure in the Navy that he first showed interest in boxing. Tall and husky for a man of his generation, Joseph was encouraged by his friends in the service to box. He quickly established notoriety as the best boxer aboard any vessel on which he served. During his brief returns home to Boston he took part in his first fights for pay, the first on January 24, 1924, against one Billy Muldoon, whom he knocked out in the first round. By the time of his honorable discharge just short of a month later, he had won a second fight and was already earning write-ups in the Boston papers.

Primo Carnera (Italian pronunciation: [ˈprimo karˈnɛra]; October 26, 1906 – June 29, 1967) was an Italian boxer, nicknamed the Ambling Alp, who became the world heavyweight champion. His career was controversial, as many believe he was "owned" by underworld figures who manipulated his career by fixing his early fights to bolster his record to give him a shot at the title.

Born in Sequals, then in the Province of Udine, now Province of Pordenone, Friuli-Venezia Giulia (Italy), Carnera was touted in America as being 6'7" tall and thus the tallest heavweight in history (up until that time), but he was actually 6′5½″ tall (197 cm) . He fought at as much as 275 pounds (125 kg),. Until December 19, 2005, when the 7 ft 1 in, 147 kg Nikolay Valuev won the WBA title, Jess Willard who stood 6' 6½" was the tallest champion in boxing history.

At a time when the average height in Italy was approximately 5 ft 5 in (1.65 m) and in the United States 69.2 inches, Carnera was considered a giant. Though an inch shorter than Willard, he was around 40 lbs heavier and was the heaviest champion before Valuev in boxing history.