Some, Gordon admits, might think this is odd, but for the Fair Go co-host, it was simply a reflection of his admiration for older sibling Miranda, who was making it big on screen in the hit local '80s show Gloss.
'I remember my flatmate [Packed to the Rafters star Erik Thomson] thinking that was a bit weird. "You've got a picture of your sister on the wall?"' the 41-year-old journalist says with a laugh. 'She had such a stellar personality, she was always a huge character in my life.'
At Miranda's stunning Wellington home overlooking the Cook Strait, it's clear the distinction between oldest and youngest still remains. Miranda loves giving Gordon a good ribbing and Gordon simply takes it in his stride.
'Miranda was the expert and I was always the boring one,' grumbles Gordon – who took over the reins of the consumer affairs show from veteran Kevin Milne – before giving his sister a knowing smile.
The two, four years apart, reminisce on their childhood in Karori, looking through a pile of old snaps. Miranda then reminds her little brother of the hilarious story of 14-year-old Gordon being sent to stay at Miranda's flat in Christchurch during her first year at Canterbury University.
'God knows why our parents let him come and stay in my flat, which was just full of all sorts and coffee mugs by the telephone with cigarette butts floating in the dregs,' Miranda says.
'I had taken Gordon to the pub to see a band and tried to get him past the doorman, who said, rightfully, "Absolutely no way."
So I took him out and said, "Get in the car. I'll lock the car, but keep your head down because it's dangerous out here." And we left him there!'
Miranda, 48, is incredibly proud of her younger brother and muses how the tables have turned in the fame game. 'Gordon has stepped in front of the camera and has got this profile. In fact, now people will say to me, "Oh, you're Gordon Harcourt's sister." People use to ask him if he was my brother,' she says with a laugh.
'I've been "Miranda Harcourt's brother" for quite a long time,' former BBC journalist Gordon reminds her, before describing his passion for catching Kiwi lowlife on the consumer affairs show.
'I bounce out of bed in the morning,' he continues. 'I can help people, I chase scumbags and, in a small way, I can make a difference. I did six years at the BBC – big issues with the world. This is the polar opposite when it comes to journalism.'
Tearing around the duo are Miranda's two eldest children, Peter, 12, and Thomasin, 10. Following in their famous mother and uncle's footsteps, they have just finished playing siblings in the feature film Existence, a post-apocalyptic drama about a family who has survived.
'It was fun,' Thomasin says of her on-screen debut, 'but also really cold and boring and tiring.''Welcome to acting,' Gordon says with a laugh.
Gordon and Miranda were brother and sister in local '80s show Close to Home and, later, Gordon played Miranda's on-screen brother in Gloss.
Peter, who bears the distinctive Harcourt look, has already made his acting debut in ads, but says a life on screen is not for him.
'I do like acting but not as a full-time job. I want to be a lawyer,' he says with a smile. 'Miranda is pretty happy about that,' Gordon adds.
Although Miranda and Gordon have had successful television careers, both agree it's tough to make a living from the stage or screen.
They encourage their children – Gordon and his wife Louise's three kids, Isabella, four, Maddie, two, and William, six months, and Miranda's Peter, Thomasin and her youngest daughter, Davida, four – to keep out of the spotlight.
'It's not a job that you can do unless somebody invites you to do it. That can be disempowering,' explains Miranda.
An internationally acclaimed acting coach, Miranda has worked alongside stars such as Dennis Quaid and Helen Hunt, and coached Carrie Underwood and AnnaSophia Robb.
She still works as an actress and features in Tangiwai, a soon-to-be released TV film about the famous New Zealand rail disaster.The family business
Acting runs in the Harcourts' blood. The matriarch of the family, Dame Kate Harcourt is an iconic Kiwi actress. The sprightly 84-year-old lives in her own flat under Miranda's house and, remarkably, is still working.
During New Idea's exclusive interview, Kate was about to dash out the door to attend the premiere of TV3 Inside New Zealand doco The Banker, the Escorts and the $18 Million, and days later she was flying to Auckland to audition for a short film.
'She is really cool,' Miranda says. 'We call her our oldest daughter, and she is like the teenager of the family. She has a lot of younger friends, so there is a constant stream of people downstairs.
I never know what the hell is going on. 'Sometimes I will lie in bed, and it's one o'clock in the morning, and Kate will come home from drinking red wine with a bunch of actors.
We often ask, "Where on earth have you been, Kate?" Gordon relishes the times when Kate works in Auckland, as his children get the chance to spend time with their Wellington-based grandmother.
'I'm really conscious of my kids knowing my mum, as I never knew any of my grandparents,' he says. 'My grandfathers were both long dead by the time I came along, and my grandmothers were both alive but only when I was very little.'
'My mum had me at 35 and Gordon at 39,' adds Miranda, who had her last child at age 44. 'And our grandmother had Kate in 1927 when she was 47!'
Despite there being only four years between them, Gordon and Miranda felt as kids the gap was 'huge,' and say it's only later in life that their bond has grown stronger.
Since becoming parents they see the value of being close as a family. 'We have seen more of each other in the last three years than we have in the previous 20,' Gordon explains.'Peter and Thomasin are always keen as mustard to come to Auckland and see everyone. You soon realise the value of cousins and how close that bond is. Miranda's youngest is exactly the same age as my oldest and they adore each other, so it is brilliant.'