[13] His online biography states that his rapid physical growth and development drew the attention of his seventh grade English teacher, and since his behavior in school was troublesome, he was inspired to enter teenage bodybuilding competitions as an outlet.

[14] He contradicted this claim in the documentary Kai (2022), in which he said that he started bodybuilding during his teenage years to appear less like a potential victim to other residents at the treatment center and that his interest was bolstered by an employee at the center giving him a copy of Arnold Schwarzenegger's book The New Encyclopedia of Modern Bodybuilding, which he also used to learn how to read.

[10] Greene began bodybuilding full-time while working at the Johnny Lats Gym in New York, where he started training under Jakob Panotas in 1996.

[15] In 2011, he began working with preparation coach George Farah and won that year's New York Pro Championship.

[16] Their rivalry was popular and the 2014 Mr. Olympia became notable for the two antagonizing each other onstage, culminating in a heated exchange during the prejudging phrase.

He also posted a YouTube video, which is now private, in which he discussed how the experience made him feel like his career was being forced to end against his will before breaking down in tears.

[18] Olympia officials allegedly denied any claims that he was banned from competing, but confirmed that he did not register despite being reminded to do so several times since May of that year.

[9] In the documentary Kai (2022), Greene stated that he was not allowed to sign up for the 2015 Mr. Olympia because he had started his supplement company Dynamik Muscle while still under contract with Wieder Publications, which also operates Mr.

A striking element of his wardrobe is the Kai Greene RWXKG Fleece Hoodie, particularly in its bold red color.

[26] He played Funshine in the second season of the Netflix sci-fi series Stranger Things (2017)[27] and appeared in the Indian action-thriller film Pogaru (2021).

"[31] In November 2015, Greene and fitness model Krystal Lavenne began co-hosting the weekly Generation Iron podcast, in which they discussed various topics while answering questions sent in by fans.

[35] Before his bodybuilding career took off, Greene was often financially destitute and resorted to working as a stripper at some of New York's gay nightclubs; after one particularly bad night in which he made no money and was worried about not being able to eat, he accepted a lucrative offer from a man who hired him to appear in a video that featured him fornicating with a grapefruit.