Ronnie Threadgill was executed at the state prison in Huntsville after the U.S. Supreme Court rejected his final appeal about an hour earlier, KWTX-TV, Waco, reported.
The TV station said Threadgill's final words included saying he was "going to a better place."
Threadgill was convicted for the April 14, 2001, shooting death of Dexter McDonald, 17.
His was the third execution in Texas this year, KWTX-TV said.
2014: The Year in Music [PHOTOS]