He is one of the most vivacious and straight-talking members of the clergy - and once chopped up his dog collar on live television to protest against Robert Mugabe's rule in Zimbabwe.
So when the Archbishop of York, the second most senior figure in the Church of England who will step down in less than a year, was asked if he would like to stay on beyond the compulsory retirement age of 70 if he could, he didn't mince his words.
Perched on a wooden garden bench, dressed in a floral multicoloured summer shirt and matching crucifix, Dr John Sentamu told The Telegraph: “The reason I think there is a limit on the retirement age of archbishops is that you can go gaga really and start embarrassing everybody!
“There is nothing more terrible than that, when someone is in their prime and can do a wonderful job. It doesn’t help in any way – it doesn’t help the person, it doesn’t help the church either. “But I give thanks to God because I’ve gone through a lot of major health problems – five operations in four years – but my health is very very good at the moment.”
The archbishop spoke out from the gardens of a picturesque pilgrimage site called Taizé in the centre of France on Friday, where he was enjoying the final few days of a week-long pilgrimage with dozens of children from five schools in his diocese.
He is due to step down on June 7 next year, three days before his 71st birthday, after being given special permission by the Queen to extend his term.
Despite his clear enthusiasm and commitment to carrying on his duties for as long as possible, he said he is feeling positive about retiring and suggested he will be limbering up for new challenges ahead during his final months in office.
Chuckling and beaming from ear to ear, he said: "I say to my clergy that they are never retired, they are just re-tyred. They just get new treads on their soles. So I hope to be re-tyred!"
There is intense speculation over who will replace him - with some predicting it will be the Church of England's first female archbishop.
“They were given nearly two years warning that I am going and the process of nominating my successor has already began so I’m hoping that it won’t be very long before people know who my successor will be," he said.
“We tend to take nine months a year. I don’t think that will be the case this time.”
Dr Sentamu, who was born in Uganda and has 12 brothers and sisters, became Britain's first black archbishop in 2005, almost thirty years after he was ordained.
For the last week he has been among throngs of Christians who flocked from all corners of the globe to the monastic fraternity Taizé, perched on sweeping hills north of Lyon.
One of the world's most important pilgrimage sites, it attracts some 4,000 worshippers every year, mainly from Roman Catholic and Protestant communities from more than 30 countries across the world.
Founded in 1940 by Roger Louis Schutz-Marsauche, it promotes Christian unity between churches - making it a magnet for different cultures and traditions.
The archbishop joined 100 monks, known as 'the brothers', who live at the site to host 100 children from Yorkshire schools who are part of the Youth Trust he founded in 2009 to empower and inspire the next generation.
And he said whoever replaces him should continue his long-held passion of helping children develop confidence and leadership skills.
“I’m hoping whoever my successor is will see that work with young people is the top priority,” he said.
“I’m looking for an archbishop who will come into York and recognise that the ministry with young people is important.
“It’s nice to be in churches, confirmations and all that kind of stuff, but the work with young people really, yes it’s hard, but it’s also very exciting.
“So the missions matter, young people matter, and you do what the ordinal says: he must – he or she - must know their people and be known by them.”
At morning prayers, led by the brothers, signs emblazoned with the word 'Silence' were held as the congregation sang along to sultry hymns ringing out from the organ.
Brother Githinji, from Kenya, told pupils during a Bible study class afterwards: "The icon of Jesus is like the icons of Facebook or Twitter on your smartphones – it opens up an entire world."
But a far cry from the social-media obsessed perspective of millennials, they amused themselves with clapping games and 'Taizé Twister', which involved standing on wooden tables in the courtyard.
They sang Shakira's 'Waka Waka' pop anthem during lunch, which consisted of vegetarian chick peas with cheese and a boiled egg.
Isaac Farrar-Lievesley, 15, from Abbey Grange Church of England Academy in Leeds, told The Telegraph: "We asked the Archbishop of York all sorts of questions.
"One person said 'how do you get a frisbee down when it's stuck in a tree?' and he said 'climb up and get it!'"
He also said the trip had renewed his faith, adding: “I just burst into tears suddenly. I felt that the Holy Spirit was within me.”
Brother Jasper, who has been living in the Taizé community for the last 12 years, said the community attracts young people by restricting the age of people who can attend.
"Those aged 18 to 30 can come whenever they like, but anyone older than that is only permitted entry once a year," he said.
"It means when youngsters come they can look around and see people of their own age and feel like they belong."
The community lives a life of simplicity without luxury, with its income coming entirely from visitors' donations and sales in the gift shop - stocked with handmade pots lovingly crafted by the monks.
Outside the main prayer hall, two police officers from the local gendarmerie stood guard - an upsetting reminder of the need for extra security following the tragedy which shook the community in 2005.
Taizé's founder Brother Roger, a Swiss-born Protestant pastor, was stabbed to death in front of worshippers by a woman who claimed she was enraged at not being able to attract his attention.
Amid a spate of terror attacks across France, and the horrific murder of Brother Roger, beefed up security at the secluded commune became a necessity.
Last year nine soldiers guarded the site – reduced to two this year.
The archbishop said: “What we need to do is make our faith really have a human face, not a religious face because that is what is causing all of the trouble.
“When you injure another person – it doesn’t matter if they are Muslim, atheist or whatever – you suffer in the same way like another human does”.
Brother Matthew, who has lived at Taizé for 33 years, said the community is still recovering but its core remains strong.
"The heart of life here hasn't changed - we still pray three times a day," he said.
"Prayer is like breathing to the brothers. If you take a brother out of Taizé then they don't just stop breathing."
He said Taizé brings people of different nationalities together who might not otherwise grow to understand each other.
"It seemed impossible at one time that Eastern Europeans would come here, or that Russians and Ukrainians, or Bosnians and Serbs would mix.
But we are all part of the same European family."
The archbishop revealed that he thinks the Brexit vote should have required a two thirds majority and was too close to provide a mandate.
He compared the referendum to the “battle” to grant women the right to be ordained as bishops 25 years ago.
“The legislation for women bishops failed because of 12 votes in the House of Laity – it didn’t get its two thirds,” he said.
“A much higher threshold will always settle things better than just a simple majority This is why I think on Brexit it should have been two thirds – it was far too close.”
The archbishop said he had a particularly upsetting experience with members of his Youth Group in Taizé the year the referendum was held.
“What is strange is we came here in 2016 and left on a Saturday, getting out of Europe happened on Thursday, result was on Friday, my group was just in tears throughout.
“They were apologising to quite a number of children and saying ‘actually we love you, we don’t hate you, those who voted out voted out but we love you’. It was difficult actually.”
Two years before the referendum, the Independent Inquiry into Child Sexual Abuse was also launched to investigate serious concerns that some organisations – including the church - had failed and were continuing to fail to protect children from sexual abuse.
The archbishop, who has given evidence at the inquiry, said: “I think we need to be transparent
“This is not embarrass anybody or to be gung-ho. We must look at ourselves and be accountable, simply because you’ve got a gospel of the love of God – as a Christian that should be driving our transparency and accountability.
“We can’t hide behind anything really because, after all, we are told by Jesus that everything which is in secret one day will be revealed on the day of judgement, so why not deal with it now?”