Hooper, 39, was executed by lethal injection and was pronounced dead at 6:14 p.m. at the state penitentiary in McAlester, after his final efforts to get the courts to stop his execution failed, KOCO-TV, Oklahoma City, reported.
Hooper was the fourth inmate put to death in Oklahoma this year.
Hooper's lawyers had tried to convince the courts -- all the way up to the U.S. Supreme Court Tuesday -- that the combination of three drugs Oklahoma uses for executions is unconstitutional, the TV station said.
Hooper was found guilty of first-degree murder in the 1993 slayings of Cynthia Lynn Jarman, 23, and her children, Tonya, 5, and Timmy, 3.
Notable deaths of 2014 [PHOTOS]