Don, 69, grew up in Cambridge and joined the brigade (then called the Cambridge Fire Board) at 19, just weeks after marrying his now wife of 50 years, Jocelyn.
He started as a firefighter on November 3, 1968 and four years later took on the role of motorman (driver).
He became senior station officer in the 1990s and chief fire officer in 1994, a position he has held for 25 years.
Although Don has seen some grim sights, he's also had many memorable call-outs, including a cow stuck down a well that was lifted out and revived.
"We pulled it up with a front-end loader, gave it some air and the next day the cow was up eating grass."
He's also saved cats from trees, kids with fingers stuck in sink holes and people with pitchforks through their feet.
"It's hard to count the lives saved, but I know we've had success," Don says.
Being able to attend day-time calls is a prerequisite to being a firefighter in Cambridge.
For Don, this has meant always being available.
"I've missed out on family parties and birthdays, had to leave restaurants in the middle of dinner, that sort of thing. You just have to up and leave."
Don says his family's support — especially his wife Jocelyn — has been the key to his long service.
"I have full backing and full encouragement from my family, so it's never been an issue."
Firefighting runs thick in the family's blood.
Don's father-in-law Howard "Bush" Hooker was also a firefighter in Cambridge, serving the brigade for 48 years.
Don and Jocelyn's son, Richard Gerrand, is a senior station officer for Cambridge, and has just marked 30 years volunteering.
Grandson Kase Gerrand, 18, started volunteering in the Cambridge brigade two weeks ago.
Don is a panel-beater by trade and has always worked full-time along with volunteering.
A big part of volunteering includes attending meetings, practices and working bees to keep the station in top shape.
"It's always noted that our station is one of the best-kept in the country," Don says.
"It's something that was always ingrained into me by my father-in-law."
There's also a lot of fundraising involved to purchase tankers, with Don helping to fundraise for and purchase six tankers for the brigade.
On Saturday night Don received a gold medal from the United Fire Brigade Association to commend his 50 years of service at an event in the Cambridge Town Hall.
He is the second member to receive the honour, following on from deputy chief fire officer Winston Steen, who has now been serving 55 years.
It'll be a nice addition to his host of other medals, including a Queen's Service Medal for services to the New Zealand Fire Service.
For now, it's full steam ahead as Don continues to serve the Waipā and respond to fire emergencies.
He has no plans to retire, saying he "hasn't given it any thought".