Leo Del Pinto, who was 25, died after being shot in the face and chest in the town of Pai in January 2008. His friend Carly Reisig, of British Columbia, was also shot in the chest but survived.
The off-duty police officer, Sgt. Uthai Dechawiwat, initially pleaded not guilty to murder with intent and attempted murder, but changed his plea to guilty a couple of weeks ago.
The former officer was already serving a sentence for beating his pregnant wife to death.
Ernie Del Pinto and his wife, Clara, made the trip from Calgary to Thailand to observe the sentencing.
"I wish it could have been 50," said Ernie Del Pinto, reached in Thailand by The Canadian Press.
"But you know what — I guess people like myself can't be choosy so I will take what I can get. I'm happy it was 37 1/2."
The trip marked the first time the Del Pintos have visited Thailand since their son's death. They intend to visit the spot where he died to try to understand what happened.
The still-grieving father said his son was a "good boy" who didn't deserve to die. The shooting has put him "through hell for five years," he said.
"I'm lost without my kid," he said. "It was a senseless death. It's just so frustrating."
But he said the sentencing has given him some solace.
"It's given me comfort in the sense that I know we got a killer off the street," Del Pinto said.
"We know he will be in there for a long time and in fact he's probably going to die in prison."
Lynne Yelich, minister of state for foreign affairs and consular services, said the federal government welcomes the court decision and thanks the Thai government for their ongoing co-operation in resolving the case.
“We understand that this has been a difficult time for Mr. Del Pinto’s family and friends and our thoughts continue to be with them," Yelich said in a statement Tuesday night.
“Canadian officials have been in regular contact with the family since this tragic event in Thailand and continue to offer support.”