Wise testified that he couldn't stand to see his wife in pain.
"She opened her eyes and looked at me like she was in pain, and a tear rolled down her cheek," Wise told the jury. "I decided then what I was going to do."
Hours later he returned to the hospital with a gun.
"My recollection is that I walked in there, and within two minutes, I kissed her on the cheek and shot her," he said.
Wise told police he then intended to kill himself, but the weapon jammed.
Mercy is not a defense to a murder charge in Ohio.
Defense attorney Paul Adamson said in closing arguments Friday that Wise acted out of love.
"He fully believed he was doing the right thing, not the wrong thing," Adamson told jurors.
After the verdict, Summit County Assistant Prosecutor Brian LoPrinzi said Wise declined an offer of a reduced charge of manslaughter, which would have carried a maximum 14-year sentence. Wise will have to serve a minimum of 23 years, LoPrinzi said.