LONDON, ENGLAND -- Prince Harry, once known as the cheeky royal with a penchant for parties, has undergone a pretty remarkable transformation over the years.

As he ascends to the fourth floor, the Duke of Sussex's journey from a young playboy prince to a purpose-driven public figure has captivated global attention -- both good and bad.

His life has been shaped by the legacy of Princess Diana, his experiences in the British Army, and of course, his relationship with Meghan Markle.

Harry's path to 40 has been defined by significant milestones and challenges. From his time at Kensington Palace to his current life in his Montecito mansion, he has navigated the complexities of royal duties, personal loss and public scrutiny.

His work with charitable organizations in Lesotho and Botswana, his candid discussions about mental health, and his decision to step back from being a working royal have all contributed to shaping the man he is today.

The evolution of Prince Harry: From party prince to purpose-driven duke

Prince Harry's journey from a carefree royal to a purpose-driven public figure has been defined by several pivotal moments, all lived out in the public eye. His early years were shaped by the tragic loss of his mother, Princess Diana, when he was just 12 years old. The image of Harry walking solemnly behind Diana's casket endeared him to the British people, but also left a profound impact on his life.

Harry's path to maturity was not without its challenges. In 2005, he faced intense criticism for attending a party wearing a Nazi uniform, an incident he later apologized for as a serious error of judgement.

However, it was his military service that proved to be the making of him. Entering the army at 20, Harry served for 10 years, including two tours in Afghanistan. This experience transformed him from a boy to a man, instilling in him a deep sense of duty and compassion for his fellow servicemen and women.

Following his military career, Harry channelled his experiences into meaningful initiatives. Inspired by the Warrior Games for injured U.S. servicepeople, he founded the Invictus Games in 2014. This international sporting competition for injured and sick veterans became a cornerstone of Harry's public work, showcasing the 'unconquerable' spirit of service members and their families.

Prince Harry slides a curling rock into place

Royal commentator Christine Ross says this is a huge part of his legacy.

“I think the Invictus Games have become a defining symbol for Prince Harry, from the success of the first games to their continued success and progress,” Ross told me.

“He is so committed to supporting veterans and every event connected with Invictus is a shining moment for Harry. Over the last 40 years, we’ve seen him as a cheeky young boy, a young man following his mother’s coffin, a soldier, brother, friend, and now as a husband and father. I think he would most like to be defined by his work with the military and as a family man,” she said.

Coping with media scrutiny

The Duke of Sussex has had to contend with relentless media attention throughout his life. This reached fever pitch after his relationship with Meghan Markle was made public.

In a statement in 2016, Harry expressed his concern over the “ruthless campaign” waged against his wife, Meghan Markle, by the British tabloid press.

He highlighted the human cost of this “relentless propaganda,” drawing parallels to the treatment his mother, Princess Diana, endured.

Prince Harry and Meghan arrive in Colombia

Harry's fear of “history repeating itself” underscores the profound impact media intrusion has had on his life and relationships. He has also been open about his mental health challenges, revealing that he sought counselling years after his mother's death.

He acknowledged struggling with aggression, anxiety during royal engagements, and being “very close to a complete breakdown on numerous occasions.”

In his memoir, "Spare," Harry admitted to using cocaine at 17 and later turning to alcohol and experimental drugs to cope with his emotional pain. He described the period from 28 to 32 as a "nightmare time" in his life, experiencing panic attacks and severe anxiety.

A new chapter: Life beyond the palace walls

Prince Harry and Meghan Markle's journey beyond palace walls began with their announcement to step back as working members of the Royal Family in January 2020. The couple expressed their intention to balance their time between the United Kingdom and North America while becoming financially independent. This decision came after months of reflection and internal discussions, as well as intense media scrutiny, as they sought to carve out a progressive new role within the institution.

Following their departure from royal duties, the Duke and Duchess of Sussex moved to California in June 2020. They settled in Montecito, where they now reside with their two young children. The couple has focused on establishing their independence, launching the Archewell charitable foundation and entering into commercial arrangements with private companies. They have also created their Sussex.com website, which highlights their efforts in shaping the future through business and philanthropy.

Despite their desire for a more independent life, the Sussexes have faced challenges in balancing privacy with their public roles. They have been vocal about their experiences, participating in high-profile interviews, most memorably with Oprah, and releasing a Netflix docuseries. While they have not cited privacy as the reason for stepping back from royal duties, they have continued to advocate for greater boundaries around their personal lives.

The couple's approach reflects an ongoing negotiation between maintaining privacy and using their platform to share their perspectives and experiences. This is an approach that has more than riled his family. As it stands, the relationship between Prince Harry and the Windsors, particularly his father and his brother, is fractured to say the least, as has been since his decision to step back as a working royal.

Reflecting on personal growth and future aspirations

As Prince Harry turns 40, he stands at a crossroads, reflecting on the journey that has led him to this milestone. Harry's current focus lies firmly on his life in the United States. He has no interest in returning to royal duties in the U.K., instead dedicating his energy to causes he cares about like the Invictus Games, Archewell and his family life in California.

As a hands-on father to Archie and Lilibet, Harry has embraced the role he most desired. His domestic life in Montecito is filled with beach days, dog walks, and school runs, reflecting a shift in priorities from his previous royal lifestyle.

Harry, Meghan, Archie

Looking ahead, Harry aims to expand his humanitarian work while maintaining a balance with his family life. He plans to dedicate more focus to the Invictus Games, with the next event scheduled for 2025. Additionally, Harry is exploring new projects, including initiatives related to mental health in schools and digital wellness.

As he enters his fifth decade, Harry told the BBC in a statement that he remains committed to the Sussex mission of "showing up and doing good," while striving to move forward rather than dwell on past grievances.

But as he goes into his 40th year, the rift between Harry and his family remains.

“For any of us a milestone birthday prompts reflection and for Prince Harry there has indeed much to take stock of in recent years,” says royal commentator Sarah Hewson. “The move to California, stepping back from royal duties, the rift with his family, the death of his grandmother Queen Elizabeth II and his father’s accession to the throne.”

Hewson said Harry is done with looking backwards, and it’s all about moving forward now, but adding “it’s not entirely clear what that looks like.” Meghan has her new product line, American Riviera Orchard and a Netflix lifestyle show to come; for Harry there’s a Netflix documentary series on polo along with his charitable projects.

“But as for his day-to-day purpose and where he goes from here as he enters the next chapter in his life, the jury is out. What is certain is that the deep faultlines between Harry and his brother remain, with the pair not even speaking at their uncle Lord Fellowes’ funeral. Despite reports that he wants to ‘find a way back,’ there are no signs of that being a genuine prospect right now,” said Hewson.

With Harry celebrating his birthday on Sunday in Montecito, how can we expect the Royal Family to mark the day? Royal expert Christine Ross says, “I’m confident there will be private video calls and text messages sent to Prince Harry on his birthday from his family. The social media posts we’ve come to know are generally reserved for working members of the Royal Family.”

As Harry looks to the future, his goals centre on expanding his charitable work while maintaining a balance with his family life in California. His dedication to the Invictus Games and new initiatives in mental health and digital wellness showcase his ongoing commitment to making a positive impact.

Whatever path Harry chooses for his future, his journey serves as a reminder of the power of personal growth and the importance of forging one's own path, even in the face of public scrutiny and expectations.