Prince Louis took control of a digger as royals joined the Big Help Out day of volunteering on Monday, while his grandfather the King issued “sincere and heartfelt thanks” to the nation for the coronation festivities.
The young royal joined Prince George and Princess Charlotte in helping renovate a Scout hut site in Slough, Berkshire under the watchful eye of their parents the Prince and Princess of Wales.
Eager to try everything from shovelling sand to painting a planter base and wheeling a barrow, the five-year-old royal ended the day splashed with paint but got his reward - a marshmallow-and-chocolate biscuit sandwich.
Later, the five-year-old prince was given the task of filling a wheelbarrow with builders' sand and he focused on the job, diligently shovelling the material before wheeling the barrow himself.
Nearby, George was given a drill and screwed wooden planters together, helped by a volunteer, as his father also assembled the boxes and at the end William quipped they would have to “clean up my mess”.
Kensington Palace described the event as Louis' first royal engagement, although he has attended a number of high-profile royal events it is thought the Slough visit was the first time the prince has actively engaged with the public.
Matt Hyde, chief executive of The Scout Association, said the royals “had an incredible time.”
Elsewhere, the Archbishop of Canterbury donned a denim Bon Jovi apron as he served lunch at a homeless charity, two days after crowning King Charles.
Justin Welby protected his clerical collar with the pinny which featured the rockers' winged emblem as he lent a hand at Catching Lives in Canterbury.
Lambeth Palace, the Archbishop's office, said it was delighted with the "enthusiasm and support" for the King and Queen's "joyful and inspiring" coronation service.
The Archbishop, who is patron of the charity, was joined by his wife, Caroline, as he handed over plates of cottage pie while working in the kitchen during the national volunteering drive on Monday at the end of the coronation weekend.
The Duke and Duchess of Edinburgh helped at a puppy class for trainee Guide Dogs in Reading, while Princess Anne attend a County Civic Service recognising local volunteers in Gloucester Cathedral.
Later Buckingham Palace issued new portraits of King Charles, Queen Camilla and the senior royals from coronation day, taken by former Tatler photographer Hugo Burnand who took the couple's official wedding photos in 2005 and for William and Kate's nuptials in 2011.
Among them, the King was captured in his full regalia - wearing the Imperial State Crown, holding the Orb and Sceptre with Cross, and dressed in his regal purple tunic and Robe of Estate, seated on a Throne Chair in the Throne Room at Buckingham Palace.
Camilla was pictured alongside the King, and also in a solo portrait, wearing Queen Mary's Crown, with the train of her lengthy embroidered Robe of Estate spread in front of her.
The working royal family - the Prince and Princess of Wales, the Edinburghs, the Princess Royal and Vice Admiral Sir Tim Laurence, the Duke of Kent, the Gloucesters and Princess Alexandra - were also photographed stood with the King and Queen in the images by Hugo Burnand.
As the weekend of festivities came to a close, the king issued a special written coronation message, saying: "We thank you, each and every one."
The king, signing his words Charles R, said he and Camilla gave “our most sincere and heartfelt thanks to all those who have helped to make this such a special occasion”.
He used his message to issue an affirmation for the rest of his reign, saying he and Camilla would “now rededicate our lives” to royal service.
He added: “To know that we have your support and encouragement, and to witness your kindness expressed in so many different ways, has been the greatest possible coronation gift, as we now rededicate our lives to serving the people of the United Kingdom, the Realms and Commonwealth.”
The king also paid tribute to the “countless people who have given their time and dedication to ensuring that the celebrations in London, Windsor and further afield were as happy, safe and enjoyable as possible.”
Meanwhile, Scotland’s first minister said some people will be uncomfortable over the amount spent on the coronation during a cost-of-living crisis.
"I made it pretty clear that I hope that the costs would be kept to a minimum," the Hamza Yousaf said during a visit to a community larder in Dundee as party of the Big Help Out. “I think a number of folk will have felt uncomfortable with the costs that were involved.”