For 41 years, he has worked his way up through the firefighters' pecking order to sit in the number one seat in the busiest fire engine in Otago.
"I sit in the back seat on the left-hand side, closest to the pump.
"I'm the squirt man. I do all the squirting."
On average, the engine attends about 1000 callouts every year and Mr Walker has been on board for many of those.
But last night was the 64-year-old's last night on duty.
As of 6am today, he is retired.
"I've kept myself really fit and I've got good health.
"I feel quite lucky to have that.
"But it gets harder, the older you get.
Tramping up and down stairs in high-rise buildings, carrying about 30kg of gear over your shoulder.
"I want to retire while I still have good health, and spend time with family," he said.
"I've done shift work for 48 years, so I'm looking forward to having normal days again."
Mr Walker said there had been countless career highlights, and the things that he would miss the most next week would be his colleagues and the excitement of turning out of the station with lights and siren on.
"I've always loved that.
"But you get absolutely soaked in this job.
"That's something I won't miss, especially in the winter.
"It's quite unpleasant," he said.
Despite the soggy clothing, Mr Walker believed it would take him some time to be totally retired from firefighting.
He will volunteer during the day at Ravensbourne Fire Station.
"I've got fire in my blood.
"I want to give my local station some support because it's difficult to get volunteers for the station during the day."
Mr Walker said he had no plans to celebrate his retirement last night.
"All I hope is that tonight will be busy."
