King, a 6-foot-7 forward, will have two years of eligibility remaining after sitting out the 2015-16 season. He chose the Crimson Tide over SEC rivals Ole Miss and Arkansas, while UNLV, Miami and others were also in the mix.
"Family, man," King told ESPN.com. "I felt it from the moment I stepped on campus. We're trying to put the basketball program on the map."
King, who visited Alabama on Thursday, averaged 7.2 points and 4.8 rebounds per game during his sophomore season. He was ranked as the No. 37 prospect in the Class of 2013.
"They're trying to give me back the confidence I had in high school," King said.
This is the second commitment for Alabama since Avery Johnson took over for Anthony Grant. He previously added Dazon Ingram, who had decommitted from the Crimson Tide after Grant was fired.