STAMFORD, Conn. —Insurance industry veteran Robert Clements, a former Marsh & McLennan Cos. Inc. executive who played a key role in developing the Bermuda market, died Saturday of esophageal cancer at his home in Stamford, Conn. He would have turned 78 Tuesday, according to his family.

Mr. Clements most recently was co-founder and a director of Hamilton, Bermuda-based specialty insurer Ironshore Ltd.

He also founded brokerage firm Integro Insurance Brokers in 2005 and Bermuda-based insurer and reinsurer Arch Capital Group Ltd. in 1995. In addition, he helped establish ACE Ltd., XL Capital Ltd. and Mid-Ocean Reinsurance Ltd. in Bermuda.

Prior to those ventures, Mr. Clements had a long career at New York-based MMC, where he was president and a member of the board of directors. He also founded Marsh's private equity business, MMC Capital Inc., and served as its CEO.

Mr. Clements was a non-executive director of several companies. In addition, he was chairman emeritus of the College of Insurance and former chairman of the board of overseers of the School of Risk Management at St. John's University.

Mr. Clements began his career at Royal Insurance Co. in 1957, according to the Insurance Hall of Fame, into which he was inducted in 2007. He joined MMC in Toronto in 1959, where he worked until he moved to its New York headquarters in 1975 and held a number of senior positions. He was elected vice chairman and president of the publicly held holding company in 1992.

He also founded and served as CEO of the firm's private equity business, MCC Capital, before retiring from Marsh in 1996.

“It's a very sad day for the insurance world,” said Charles A. Davis, CEO of Greenwich, Conn.-based Stone Point Capital L.L.C., which the former principals of MMC Capital formed in 2005 following MMC's divestment of the private equity subsidiary. “He is a legend. He created MMC Capital” and was instrumental in all the private capital formation in the insurance industry over the past 20 to 30 years. “He'll be missed by everybody in the business.”

Mr. Davis described Mr. Clements as “very warm, very engaging, very creative, a real family man. Just a special guy on a whole bunch of levels.”

Peter Garvey, president and CEO of New York-based Integro, said: “He had a very unique perspective. He always seemed to come up with an observation that nobody else quite saw. He liked to think deeply about things, and because he was so intelligent, that was very valuable to all of us around him.

“He had a style of speaking slowly and choosing his words carefully. He liked to tell me that that was a device to buy him extra time to think about the answer, which was an indication of his great sense of humor, but I always thought that, more than most people, Bob knew the power of words and wanted to be certain that people understood him,” said Mr. Garvey.

“He was for people,” Mr. Garvey said. “Everybody who knew him knew what a really caring individual he was. In spite of his great success in the business, he cared about everybody that he came to know. That was a very endearing quality.”

“I viewed Bob as a friend, a business colleague and great counsel for me at Ironshore. We're going to miss him,” said Kevin Kelley, chairman and CEO of Ironshore Inc.

“He had an uncanny ability to see and sense opportunities, how to gather people and orchestrate that was unique,” Mr. Kelley said, noting that Mr. Clements had a long track record of building companies in Bermuda. “Bermuda will continue to be a great place for people like Bob who are entrepreneurial and who realize business opportunities don't last forever,” he said.

“Bob was a very thoughtful guy on many levels. He was truly a multidimensional individual,” Mr. Kelley said. “He understood business and he understood family, and he was very charitable with his time.”

Dinos Iordanou, chairman and CEO of Arch Capital Group Ltd., said: “I couldn't say enough about him. He was a terrific leader and visionary, always looking to make sure that the industry was responding to the needs of the customer, and that's what drove him to create” several different insurance enterprises, said Mr. Iordanou.

Mr. Iordanou said he knew Mr. Clements for 30 years and “we have always had very professional interactions. He was extremely intelligent and straightforward in his approach to the business and it was a pleasure doing business with him. That's why I chose to be part of his team” at Arch. “His vision will be sorely missed. He was an individual who never really set boundaries in his thought processes about what the next step should be in the insurance world, and he did it extremely well.”

J. Patrick Gallagher Jr., chairman, president and CEO of Itasca, Ill.-based Arthur & Gallagher & Co., said in a statement: “Bob Clements made a definite mark on the insurance industry. He was a well-respected competitor as well as a creative thinker who found ways to bring capital to the marketplace when his clients needed it the most. Our industry has lost a true innovator.”

Brian Duperreault, president and CEO of Marsh & McLennan Cos. Inc. and former chairman of ACE Ltd., said in a statement: “Bob Clements was a giant of the global insurance industry. From his time as president of MMC, he went on to play a leading role in the foundation of the Bermuda insurance market. Our industry, and our clients, owe him a huge debt of gratitude. Our thoughts and prayers are with his family.”

James H. Veghte, chief executive of XL Group's reinsurance operations, said in a statement: “Those of us at XL who were fortunate to have had the opportunity to work with Bob over the years are extremely grateful to him for his leadership in the formation of our organization and his service on our board of directors. He was a pioneer in every respect, and all of us are tremendously saddened by his passing.”

According to his family, throughout his life, Mr. Clements spent many hours in canoes and kayaks on New England rivers, his beloved Long Island Sound, and in the Caribbean. He found both relaxation and new ideas for business while paddling on the water with family and friends or alone, and continued to kayak as recently as this August. While a determined but relaxed paddler, he was known to family and friends as fiercely competitive on the tennis court, giving no quarter to friends, children and grandchildren enlisted into tournaments that he organized whenever he got the chance, according to the obituary released by his family.

A life-long lover of jazz and a piano player himself, Mr. Clements was lucky enough to meet Louis Armstrong in a small jazz nightclub in upstate New York in the early 1950s. Mr. Armstrong invited Mr. Clements and his friend to share a drink and a meal in his dressing room. The photographs he always kept near him in his office were those of wife, his children and grandchildren, and a signed photograph of the meeting with Louis Armstrong a half-century ago.

According to his family, Mr. Clements was born in 1932 in Chicago, the oldest son of John Clements and Mildred Chapman Clements. After his graduation from Evanston High School in 1950, Mr. Clements attended Dartmouth College, where he majored in government. After graduating from Dartmouth in 1954, Mr. Clements served in the U.S. Army and was stationed at Fort Bliss in El Paso, Texas. Mr. Clements and his family set up the Robert Clements Professorship of Democracy and Politics at Dartmouth College.

Mr. Clements is survived by his wife of 55 years, Marilyn; four children; and 12 grandchildren.

A memorial service will be scheduled soon, according to Mr. Clements' family. In lieu of flowers, donations may be made to Long Island Sound—Soundkeeper, www.soundkeeper.org, or Partners in Health, https://donate.pih.org/page/contribute/donate.