Bill Beaumont has been unanimously elected as chairman of World Rugby.
The 64-year-old England Grand Slam-winning captain will take up his post on July 1, World Rugby announced.
Beaumont succeeds Frenchman Bernard Lapasset, who had previously announced he would not be seeking-re-election, while former Argentina scrum-half and skipper Agustin Pichot was elected vice-chairman.
Both Beaumont and Pichot stood unopposed. They were unanimously voted in by World Rugby Council members, meeting in Dublin.
Beaumont, the Rugby Football Union and Six Nations Rugby chairman, was World Rugby vice-chairman from 2007 to 2012, while he also served on World Rugby's executive committee and Rugby World Cup board.
He won 34 caps for England, highlighted by him leading his country to a Five Nations Grand Slam in 1980, while he also captained the British and Irish Lions, in addition to serving as Lions tour manager in New Zealand 11 years ago.
"I am honoured to accept the mandate of council to serve as World Rugby chairman at what is an exciting and pivotal time for the sport," said Beaumont, who will serve a four-year term.
"Rugby has experienced significant and rapid growth, which is a credit to Bernard Lapasset and his leadership over the past eight years.
"The sport is in excellent health, and over the next four years there will be many great opportunities to further develop and grow the game.
"However, we cannot be complacent.
"Rugby, like all sports, faces challenges, and my manifesto outlines the five priorities focused on addressing these. These priorities are continuing to protect players, preserving integrity, enhancing global competition, optimising partnerships and empowering and strengthening unions.
"I will nurture the roots of rugby, our fundamental values and financial security, and will make rugby decisions for rugby reasons.
"As World Rugby chairman, I will work with unions over the next four years to deliver healthy, sustainable growth for the game we all love."
Outgoing chairman Lapasset added: "Rugby is in great shape around the world, and I am proud that I vacate the position after eight wonderful years, during which we have achieved record participation, increased interest and engagement, Olympic inclusion and record-breaking Rugby World Cups.
"I leave with a dynamic new governance model implemented, and I am delighted that my colleague and friend, Bill Beaumont - with a clear vision and strong passion for the global development of rugby - will drive the game into this exciting period.
"The future is very bright for our sport with the Rio 2016 and Tokyo 2020 Olympic Games, and a ground-breaking Rugby World Cup in Japan all major milestones before the end of this decade."