Rapper Kendrick Lamar was one of many high-profile supporters, tweeting "listen to this album if you feel anything. raw thoughts" - and the record peaked at number two on the United States charts.
His death was confirmed by the Broward sheriff's office. Investigators are yet to ascertain the motive behind the killing.
In December 2017, he was put on house arrest and faced more charges, including witness tampering for allegedly talking to his girlfriend while in prison. In 2016, he was arrested on charges including home invasion for a 2015 incident, and less than a month later was arrested on charges that he attacked his girlfriend, who was pregnant at the time.
In September, the 20-year-old came under fire for his music video "Look At Me", which took a controversial tone around police brutality, white supremacy and slavery. Some of hip-hop's most legendary lyricists talked about their demise in songs and videos, with both Tupac Shakur and Notorious B.I.G. doing so in the 1990s.
He made headlines last June in San Diego when he was knocked unconscious during a performance at the Observatory North Park, KTLA sister station KSWB in San Diego reported.
The rapper was on house arrest but the judge recently let him out so that he could tour.
In addition to musicians, fans of the late artist shared tributes to XXXTentacion on social media. His second album ? spent a week at No. 1 in March and featured the hit single "Sad!" which peaked at No. 7 on the Billboard Hot 100.
"His favorite thing was to just backhand my mouth", she said.