This year Mr Blackwell travelled to earthquake-stricken Christchurch to donate $15,000 to the Canterbury Youth Development Programme and $10,000 to the Emergency Care Foundation at Christchurch Hospital.
Mr Blackwell is also a trustee for the Decision Reach Youth Trust, which he set up in the Western Bay.
A humble man, Mr Blackwell had to think twice before even accepting the nomination as a finalist as Person of the Year when first contacted by the Bay of Plenty Times.
"I wanted to give it some thought, because I don't do it for this [recognition]. I'm reluctant to have my name thrown to this because it's a lot of people make this work."
What made him decide to accept the nomination - and ultimately the top honour - were his children, his occupation in the police, and the effort which went into the nomination.
"We [the police] get bagged a lot. I see the reward and return and positive enjoyment in community relationships. That's why I said yes," Mr Blackwell said.
"There's a big picture to it, it's not about me. I'm proud of what I do and the people I work with. It's tremendous, it's positive."
The charity auction has come a long way since its humble beginnings 16 years ago, when it started with "40 detectives at Bureta Park having a social afternoon with no intention of raising money".
Initially the money was raised only by adding a little extra on the ticket price - the first event raised $200 for the community. Mr Blackwell, who next month celebrates 35 years in the police, was inspired by a similar luncheon held in Auckland.
But the Tauranga event quickly grew, with quality guest speakers including Sean Fitzpatrick, Graham Henry, Nick Farr-Jones and Sir Brian Lochore, and items such as sporting memorabilia auctioned off.
"It was about having a good day, but making a good difference to appropriate worthy charities, largely within the Western Bay, which made it a lot easier when it came to approaching people," Mr Blackwell said of the event's early days.
The auction expanded again in 2004 when it outgrew its original venue at Bureta Park, and went to Baypark Stadium.
It was a big step - increasing capacity from 180 to 600 people - but the event was a sell-out hit.
Prominent New Zealand and Australian sports people continued to support the auction, many giving their time free and even donating extra money.
Some, such as Sir Colin Meads, attend every year and ring to make sure they have the date locked in their diaries.
Mr Blackwell has spent hundreds of hours each year organising the event, but like everyone else involved, he has not made a cent from it.
"I have paid for my meal every year, I don't make a dollar - no one does.
"There's a credibility around the event, no one's clipping the ticket."
Mr Blackwell has a busy job as a Tauranga police officer, and also an active family life.
But community work is second nature to him - he says it's in his DNA.
"My parents have been heavily involved in lots of things. It's a lot about who you are, and what you are, and how you have been raised."
And Mr Blackwell wants to pass that community spirit on to his children.
"I want them to understand what I do, that they can be good people and do good things, because life's not about yourself.
"Giving people opportunities is a pretty powerful thing.
"Along that road you are rubbing shoulders with quality people. The number of friendships I have made along the way, with people from all sorts of backgrounds who are high-quality givers, is incredible.
"I feel sorry for people who don't understand that.
"We make a difference. How powerful is it to hand over a cheque, two cheques for $100,000? It's incredible.
"It's better to give than receive, that's what this is all about."
Mr Blackwell's community work doesn't stop at the police charity auction.
He was inspired to set up the Western Bay of Plenty branch of the Decision Reach Youth Trust, which enables secondary school students identified as future leaders to attend courses. He is also a trustee.
Mr Blackwell is always looking for opportunities to help his causes - he asks if the story can mention that the trust is currently seeking $6000 so the students can attend a camp.
Among the other many organisations he has helped is the Child Cancer Foundation - 50 police officers shaved their heads to raise $10,000 for the organisation.
"It's trying to get them to learn and understand how important these things are. The return for us as individuals, but also the occupation we work for, is huge."
His community work is a "good balance" to his paid work as a police detective sergeant.
"In my job I've been dealing with a lot of the bottom end of society for 35 years.
"[Community work] is refreshing, it's good people doing good quality stuff. I have met plenty of those."
His work in the police was recognised with a Police QSM in 2007 - an honour he was also initially reluctant to receive.
Mr Blackwell - whose role models include his parents, Judge Paul Geoghegan, Western Bay of Plenty area commander Inspector Mike Clement and Warwick Talbot from Bay Engineers - considers himself a lucky man.
"You do good things, and good things happen.
"Life is about giving not taking, about making a difference to people who aren't as lucky as most of us.
"I am very lucky, I'm very happy with what I've got.
"I've got four very healthy children that I'm very proud of, I've got a lovely wife who is very supportive.
"Without her support a lot of this wouldn't have happened - that's a fact."
Mr Blackwell is not driven by personal financial reward, and says the community work he does is far more rewarding than "striving for more noughts in a bank account".
"Not everyone can say they are proud. That's a sad thing, but I can. I'm proud of my friends, my wife and children.
"The most important things in life are things you can't buy."
His community work has given Mr Blackwell plenty of memorable experiences and friendships.
An unforgettable moment was spending an hour with Sir Edmund Hillary, just months before his death, as he signed $5 notes for the charity auction.
"Having an hour with him was just incredible. That's what this lunch has given us - the opportunity of meeting great New Zealanders and Australians.
"If you can get involved and make this a better place to live and sit back and honestly say you have made a difference in some way to somebody less fortunate than yourself, this whole thing is worthwhile."