On the TV the other night he was labelled a pop star but Hanlon considers himself "just a lucky bastard".
He accepts he was born with talent, going on to win awards for songwriting, advertising and music albums.
Hanlon was born in the then Malaya in 1949 to a Chinese mother, Cheng Neo (Daisy), and European father Norman John (Tim) Hanlon, "who spent time in Timaru".
He was raised in Kuala Lumpur and Singapore before attending boarding school in Western Australia. He eventually settled in Auckland with his parents in the early sixties.
Hanlon doesn't know where his diverse talents comes from.
"If I knew the answer I'd put it in a bottle and sell it because of the joy that comes from it."
He suspects he was "new-age well before it became fashionable".
Musically, he confesses, he can't even write it, although it starts as tunes for him and always ends up encapsulating melody.
They aren't great works of composition but merely songs with words that matter and tunes that one can hum to.
"They called me an entertainer but I never won an award for entertainer of the year or a vocalist award so where that legend came from I don't know."
Hanlon cuts across genres, not privy to any sounds but someone who can write country, jazz or blues songs, especially ballads.
"I can write a rock-and-roll song but it's not my genre. I'd have to completely act to do it. I can never in my life write a hip-hop song."
He can sit down to entertain people or conduct an acoustic concert but points out others in the industry see him simply as a competent musician.
"I'm a songwriter who plays a guitar and if I go to a recording studio I might play a rhythm guitar on some of my tracks.
"But nine times out of 10 if we were in a recording studio and I wanted a clean record with no mistakes I would use good musicians."
He puts it down to competency and receptiveness.
"If you work with good people they bring something else to the party," he says, identifying with a songwriter who goes to a studio with his work only to find a drummer who's had a hard night the day before demanding the script be changed to acclamations of "wow".
He juxtaposes that with his main career as "creative tractor" in the advertising industry.
"I would know what the best ideas would be. It's a strange thing where you have this ego that tells you are the one that says it but you remove your ego because the most important thing is to get the best result."
It amuses him immensely that his songs were banned because of excerpts that were deemed offensive compared with the licence contemporary musicians have now.
For instance, the then New Zealand Broadcasting Commission banned his mid-1974 single, Is it Natural/I'd Rather Be a Bird, because of the lyrics "randy schoolboy".
The word "risky" was mooted to replace "randy" but Radio Hauraki came to Hanlon's rescue and played the uncensored single, which went on to claim a Rata award for best recorded composition.
"I hadn't played live for 40 years and the other day I did at a cafe just to play my new music in Auckland and a lot of people were stunned," he says of the boutique crowd's endorsement and the impending news that spawned invitations from around the country to replicate the performance.
He is mindful at least two generations probably haven't heard of him but his reappearance has sparked a rebirth of sorts.
Hanlon hastens to add he isn't remotely drawn to emulating his feats of the yesteryear.
"I'm not the slightest bit interested in going out on a tour where I'm required to be someone I was 40 years ago because I'm not who I was 40 years ago. Nobody is."
Frankly he can't sing those songs any more because the notes are elusive.
"In musical terms if I was to do Damn The Dam, it was done in G and I'd have to do it in E," he says of the 1973 release born out of a two-minute radio advertising commercial to insulate homes without mentioning the sale of the product.
"Higher Trails, which was done in E, I'd have to do in C so it won't sound the same," he says although conceding he could do a version of it.
Never having done a jingle before that, Hanlon was the only one in the brainstorming session in the advertising office that day who thought an extended version of it as a song would never sell.
"I thought I had this reputation as a bloody greenie who was always on about dolphins, Vietnam and nuclear issues," he says, feeling the world already had Bob Dylan as the global ambassador, but others disagreed with him.
He was admittedly wrong. What Hanlon thought was "flowers in the field and not grungy enough" reached No5 on the national charts, earning him a Rata award for the single of the year.
"Everybody thought I was writing about the Manapouri Hydro Dam [controversy] but I wasn't because I talk about kauri trees and there aren't any in the South Island," he says of a song that expressed Hallmark Christmas card-type sentiments but that he now accepts was right for its time.
Even if out of curiosity Generation Y was to discover his prowess as New Zealand's first significant songwriter who didn't do covers, it appeals to him to build a rapport with a younger audience.
"You won't believe how many people often ask me how I could possibly just walk away from fame.
"I would say to them, 'Do this for me. Go out to a dinner party and tell the same eight jokes. Now do it for a week and then do it for six months and a year'."
Entertainers have a propensity to revisit those jokes, as it were, but not Hanlon who started his career as a painter who intended to scale the heights of commercial-dom.
"I realised at art school that I was a good artist but not a great one so my career changed after that," he says, revealing he still picks up his brushes to tease the canvas.
"Imagine getting up to do the same thing over and over again. Do the Sunflower. That's why [Vincent] van Gough cut his ear off," he says with a laugh of the Dutch post-impressionist painter from the 19th century.
Fame, he says, is a Faustian deal, a pact with the devil, something he didn't pursue when he took up songwriting.
"Unless it's what you want you had better look out. Be careful what you wish for because it takes away privacy and completely removes your ability to observe as you become the observed."
He often wore contact lenses and shaved his hair off to drastically alter his image to be incognito.
He casts his mind back to a concert in Western Springs, west of Auckland, and bumping into a man wrapped in a blanket.
"I just realised I had bumped into Elton John. I thought this is what he has to do to avoid being crowded."
Not long after nature called and Hanlon found himself in a door-less toilet at the concert.
"And there are people there going, 'John Hanlon's in there' and here I was sitting on the toilet with diarrhoea," he says, throwing his head back in laughter. "This is not a life anyone would choose."
He suspects there's an underlying sense of enormous resentment from a generation a tier below his who feel his cohort of baby boomers stuffed up the world, quite often outlined in media.
"They don't like us and feel our generation shouldn't be allowed to vote because it's not our future.
"Basically they're saying 'Go away, you've done enough damage and we don't need you'."
While Hanlon doesn't understand the sentiment he knows what drives it.
The authors of such opinions tend to outline homophobia and gender inequalities, to name a few, to support their arguments.
"All of that is true but it is also true that we changed it and the writer completely forgot that."
Apathy from the young to abstain from voting on the grounds of his generation out-voting them, he feels, is a non-sensical argument.
"A lot of things they tend to take for granted now, such as the environment, sustainable energy and protecting animals, but we changed those things," he says although conceding there's a fair whack of ground to make in addressing gender inequalities.
Ditto the debate on high-rise buildings, something he vehemently opposed in his heyday prophetically arguing the perpetrators were only going to make it impossible for their children to buy homes.
"I bought my first house for less than my salary.
"Can you imagine anybody doing that today?
"That's not a fair world but I do understand the anger of the younger world to see [those responsible] walking away without going to jail."
The man, who lived and worked in Sydney before returning to Auckland in 2014, believes cronyism completely riddles our society today. "So I can say it's not baby boomers in general but a certain type of people."
