Prosecutors said Caleb Flynn, 40, staged a home invasion in February after shooting Ashley Flynn, a 37-year-old schoolteacher and volleyball coach, then claimed she was killed by a burglar.
In his 2013 appearance on American Idol, Flynn told TV viewers about how his wife had encouraged him to chase his dreams on the singing competition. He did not advance to the main competition in Hollywood.
With tears rolling down his cheeks, Flynn apologised in court to his family, starting with his two daughters.
"I made vows to Ashley on our wedding day. I failed in those vows," he said.
Although he admitted he lied about many things, Flynn remained adamant he was innocent.
"As I stand here before God, who is my ultimate judge, I am not lying when I say I did not kill my wife," he said.
Miami County Common Pleas Judge Jeannine Pratt on Monday said she was deeply disturbed that Flynn used his faith to hide his "deceit" and "lust.".
During closing arguments, prosecutors told jurors Flynn wanted out of his marriage when he shot his wife at their house in Tipp City, a suburb north of Dayton.
The couple's two daughters were home with their father when police arrived.
The gun used to kill Ashley Flynn was not found at the scene, and his lawyer told jurors investigators found no evidence Caleb Flynn fired a gun that day.
Prosecutors said his fingerprints and DNA were at the scene and that his devices showed him moving around the house, even though he claimed he was asleep at the time of the shooting.
The jury found him guilty of murder, felonious assault and tampering with evidence.
