Chris Jackson, royal photographer for Getty Images, has been photographing the prince on official occasions for 14 years and says that, with Harry, "you never really know what to expect."
"He is great fun to photograph, he's got a real passion and real energy," Jackson tells CNN. "(But) you've got to learn to always be ready... You learn to expect the unexpected."
Through Jackson's images and unique insights, CNN looks at the prince's tumultuous life to date and asks: who is Meghan Markle's future husband?
'There's still a lot of grief'
Prince Henry Charles Albert David Windsor was born in London on September 15, 1984, a younger brother to William and, at the time, third in line to the throne.
In many ways, Harry's childhood followed a familiar royal pattern. He attended private schools in London and Eton before training to be a soldier.
But Harry's young years were marked by tragedy. A year after his parents' very public and acrimonious divorce, Harry's mother, Princess Diana, was killed along with her boyfriend Dodi Fayed in a car accident in Paris.
The first time he cried from grief was at the funeral, Harry revealed last year in an ITV documentary marking 20 years since Diana's death
. And perhaps just once since then, he added. "There's still a lot of grief that needs to be let out."
In his youth, Harry earned the label of rebellious royal, facing accusations of underage drinking and cannabis use as a schoolboy, wearing a Nazi uniform to a costume party
at 19 and partying nude in a Las Vegas hotel
In a candid interview with the Telegraph's Bryony Gordon
last April, Harry alluded to those years, admitting that shutting down his emotions after his mother's death had a "serious effect" on his personal and working life.
"It was 20 years of not thinking about it and two years of total chaos," he said, adding that therapy helped him.
Jackson sees a prince who is now enjoying the process of shaping his identity as a royal. "As his role has developed and changed to where he is today, he's embraced it," the photographer says. "He's very comfortable in his current role."
A military man
The prince's years in the military -- first as an army officer and later as an Apache helicopter pilot -- have had a big influence on that role.
At the time, military life was another way of numbing himself to the pain of his mother's death, Harry explained last year.
"The 10 years that I was in the army, I just sort of dug my head in the sand," he told ITV. "It was just white noise."
But his experiences as a soldier also seem to have offered him a path to somewhere more positive. Witnessing war and the life-shattering impact it can have on soldiers and their families inspired Harry to launch the Invictus Games -- an international multi-sport event for wounded, injured or sick members or veterans of the armed services -- in 2014.
"Invictus has been one of his biggest achievements," says Jackson, who has photographed Harry at each of the three Games held so far, the most recent in Toronto, Canada, last year. "It certainly means a lot to everyone involved."
And it means a lot to Harry too, Jackson explains. "He feels very relaxed and at home in that environment," he says. "The fact that he served as a helicopter pilot... commands a huge amount of respect from fellow soldiers. It gives him a sense of gravitas which he otherwise wouldn't have had."
'He's breaking down barriers'
The Invictus Games project wasn't Harry's first foray into charitable work. In 2006, he co-founded Sentebale, a charity that helps vulnerable children in the tiny southern African country of Lesotho.
Following in his mother's footsteps, Harry campaigned to reduce the stigma around HIV and AIDS (famously taking a HIV test alongside pop star Rihanna during a trip to Barbados in 2016), while also co-running a mental health campaign with his brother and sister-in-law, and working to combat youth violence in the UK.
"It's been an organic process," says Jackson, referring to Harry's developing role since leaving the military. "There was no set pathway. He's had to come up with a lot of these ideas and do a lot of it on his own."
Harry explained his motivation in the conversation with Bryony Gordon last year. "The privilege comes with a huge amount of responsibility," he said. "As long as we're this age and we're still interesting, we want to make as much of a difference as we can for the better."
Jackson sees Harry as uniquely positioned to do that, given the "real warmth, real affinity" he brings with him to every public event. "He's breaking down barriers," Jackson says.
The photographer has taken countless pictures of the prince giving spontaneous hugs and kisses, and notes wryly that "on more informal engagements, Harry keeps you on your toes."
Children and adults alike respond to his natural approach, Jackson says . Some of his favorite pictures of the prince were taken in Lesotho as Harry spent time with the children being helped by Sentebale.
"It's somewhere he feels very relaxed," says Jackson. "And kids certainly get excited about seeing him. He connects with them in a very unique way."
But it's not always fun and games, Jackson points out. Harry has been taking on more formal duties as the Queen steps back from public life, making official visits to countries including Singapore, Jamaica, Nepal, South Africa, New Zealand, Oman, Brazil and Estonia in the past few years alone.
"I always love going on a Prince Harry tour," says Jackson. "He's a very powerful ambassador for the UK around the world."
That work will continue when Harry is a married man -- he and Meghan plan to focus their energies on Commonwealth projects and the prince was recently made a Commonwealth Youth Ambassador.
'All the stars were aligned'
Speaking on the day Harry and Meghan announced their engagement, the prince said it had been "hugely refreshing" to get to know -- and to fall in love with -- someone outside the bubble of royal life, someone who knew little about him.
But that also meant a huge learning curve for his new girlfriend. Harry said the pair had had "some pretty frank conversations" about the life Meghan could be embarking on. "It's a big deal," he said. "It's not easy for anybody."
As rumors of their relationship spread across the internet in late 2016, the couple was shocked by the hostility and harassment they faced. "I tried to warn (Meghan) as much as possible, but I think both of us were totally surprised by the reaction," admitted Harry in November.
But since taking the unprecedented step to berate the press and social media trolls for a "wave of abuse," life has been smoother -- and Harry is convinced he and Meghan can tackle anything together.
"We're a fantastic team," said Harry. "The fact that I fell in love with Meghan so incredibly quickly was confirmation to me that all the stars were aligned. Everything was just perfect."
"Hopefully we'll start a family in the near future," he added later.
Jackson sees the couple's closeness on every outing. "It's been great seeing the dynamic between them -- they work really well together," he says, adding: "They clearly are very fond of each other."
May 19 marks the start of a new chapter in Harry's life -- and it's an important day for Jackson too. He hopes to be positioned outside the chapel on their wedding day, ready to capture the newlyweds "stepping out into the light for the first time as a married couple."
No doubt Diana will be on the prince's mind that day. "It is days like today when I really miss having her around and I miss being able to share the happy news," he said in the engagement interview.
But he's sure his mother would have approved of his choice of wife: "I think they'd be thick as thieves, without question... (she) would have probably been best friends with Meghan."