Dedrick Williams (22) was taken into custody on Wednesday evening, two days after XXXTentacion, whose real name was Jahseh Dwayne Onfroy, was shot while leaving a motor sports dealership in Deerfield Beach, about 64km north of Miami.
The death of the 20-year-old rapper stunned the hip hop community and sparked tributes online.
Two men fled the scene in a dark SUV after one of them opened fire during a possible robbery attempt, investigators had said. It was not immediately clear if police were looking for a second suspect.
XXXTentacion, who was born and raised in Plantation, Florida, released his debut album in August 2017. His second album "?" debuted at No.1 on the Billboard 200 album chart when it was released in March.
According to local media reports, he had spent time in jail and was awaiting trial on allegations of domestic violence against his pregnant girlfriend.
Police said Williams was also charged with probation violation for theft of a motor vehicle and driving without a valid license. He was awaiting trial on Thursday.
