The Duke of Cambridge welcomed Commonwealth delegates to a global summit telling them they were part of the "mother of all networks".
William told representatives of the Commonwealth's 53 member countries, with a combined population of 2.4 billion, their gathering represented "a shared desire to make our world a better place".
Prime Minister Theresa May was missing from the launch event that showcased the best of British from the Premier League to the exploits of astronaut Tim Peake, as she was involved with the Commons debate on the attack on Syria.
Delegates from the Business, People's, Women's and Youth Forums - staged during Commonwealth Heads of Government Meeting (CHOGM) week - gave the duke a rapturous welcome when he first arrived and he joked there were "too many men screaming".
Speaking at the Queen Elizabeth II Conference Centre in central London, he added: "The Commonwealth has rightly been described as 'the mother of all networks'. There is no other organisation on earth that marries politics with the civil society and the networks that the Forums represent.
"And you are just the tip of the iceberg: there is a huge number of organisations representing every profession and walk of life who network across the Commonwealth scientists, archivists, activists, medics, museums, universities, commerce I could go on.
"These bodies, and your work in these forums, bring a world that needs more communication, not less, together. What this gathering represents is a connection based on empathy, compassion and a shared desire to make our world a better place."
William later toured an exhibition of stands collated by the Department for International Trade and the GREAT campaign, which showcased creativity, technology and innovation from across the UK.
Richard Scudamore, executive chairman of the Premier League, met William, president of the FA, with the Premier League trophy in the background, recently won by Manchester City.
He highlighted his organisation's world-wide coaching programme Premier Skills which is run in a number of Commonwealth countries as well as other nations.
Mr Scudamore said after meeting the duke: "We're proud exporters, we do an awful lot of things around the world. Obviously people watch our matches on television and that gives the extra power to get involved in doing things like Premier Skills on the ground.
"But to make these things fly you need credible leaders who people recognise and obviously the Duke of Cambridge is vastly important to us, just like when Prime Ministers stop by, both our own and prime ministers from other countries."
William also talked motorcycles with Siddharth Philip, the chief executive of Royal Enfield motorbikes - a former British firm now run by the Indian businessman who produces the bikes in his homeland but which now has its technical development centre in the UK.