Kambosos Jr. is a boxer who is always in good physical shape and at optimal weight. With an undefeated record of [19 (10KO) -0], imposing his style on boxers such as Qamil Balla, Krai Setthaphon, Rey Pérez, Richard Pena, José Pedraza, Mickey Bey and defeating the former featherweight champion of IBF Lee Selby by Split Decision (SD), at the SSE Arena in London. The victory over Selby makes Kambroso Jr. the mandatory challenger for the IBF Lightweight title, owned by Teofimo López. George is working very hard for his assault on the world title. All of his camps are done in the US, giving high priority to his sparring, getting a great set-up for their fight on June 5.

"The continuous, tireless and persistent effort will make you draw up a plan to get where you set out to" are words that any parent or coach will try to burn you when you start a sports career. This was instilled in the young Kambosos Jr. when he for the first time went down the stairs of the gym in Sydney (Australia), he knew that he was made for this sport and began to forge a boxing that gives him the nickname of "The fierce" Kambosos Jr.

He was an overweight boy, bullied and harassed by his schoolmates, he played in the local rugby league, but his physique did not allow him to contribute to the team everything he wanted. His 10-year-old weight was 135lb, currently it is the division where Kambosos Jr. enters the ring. At the age of 11 he started boxing and lost 14kg in the first months of training. His physical and technical condition progressed at an optimal rate, until he achieved a perfect physique to start competing.

Australian by birth, of Greek origin, he felt very proud to fight for Australia and proud of his Greek heritage, transforming into a Spartan warrior every time he jumps into the ring, honoring his tattoo with the inscription "Molon Labe", words attributed to King Leonidas, in response to Xerxes' demand, that the Spartans surrender their weapons: "If you want him, come and get him." This is the Spartan philosophy of Kambosos Jr., who in his preparatory stage obtained a boxing style more adapted to professionalism than to the amateur world.

He reaped victories in Russia, Ukraine, Armenia and the United States, was champion of the state of New South Wales seven times and won the national Golden Gloves five times, was a bronze medalist at the Arafura Games and lost at the 2012 Olympics. against Luke Jackson. He became a great prospect in the professional field, becoming the greatest exponent of Australian boxing, being hired by Manny Pacquiao as his greatest assistant for his sparring. His inspiration to continue winning and become world champion are his daughter Evaliah and his son Leonidas, with whom he shares the free time he has left after long physical conditioning sessions.