The 17-year-old died after taking between 15 and 18 bullets to his body.
The Mexican social media star was filmed insulting Nemesio Oseguera Cervantes also known as "El Mencho".
Weeks after he posted the video mocking the drug lord he was shot dead by an armed gang at Mentados Cantaros in Tlajomulco in in Culiacan, in the northwestern Mexican state of Sinaloa.
The popular internet personality, who went by the nickname El Pirata de Culiacan, accidentally gave away his location using Instagram.
At around 11pm on Monday night, gunmen burst into the music venue and opened fire.
They took aim at Juan and fired more than 15 times, leaving him mortally wounded.
A 25-year-old employee of the bar was also shot, they later died in hospital from their injuries.
Juan was extremely popular online, he had more than 1,000,000 followers on Facebook as well as 300,000 on Instagram and 30,000 on Twitter.
He was famous for his baby face and sense of humour, often posting pictures poking fun at the fact he was overweight.
Juan would share photographs of himself hanging out with beautiful women and drinking alcohol.
He seemed to inadvertently predict his own death, after photoshopping himself into the final photo of Tupac Shakur, taken shortly before the rapper was shot.
El Mencho is one of Mexico’s most wanted men and currently has £3.7 million bounty on his head.