S. Bruce Smart Jr., who rose from metal can salesman to chairman of the Continental Group, a Fortune 100 company with more than $5 billion in sales, and who later served in the Reagan administration as undersecretary of commerce for international trade, died Nov. 22 at his home in Middleburg, Va. He was 95.

The cause was pneumonia, said his daughter Charlotte Rogan.

Mr. Smart spent more than three decades at the Continental Group, a company previously known as the Continental Can Co., whose wide-ranging concerns included packaging, energy, forest products and insurance.

After ascending the sales and corporate ranks, he stepped down in 1985 as chairman and chief executive. His retirement came the year after the Continental Group was taken over by investor David H. Murdock and the construction and mining company Peter Kiewit Sons Inc. for $2.75 billion — at the time, according to the Associated Press, the largest private takeover in the history of U.S. business.

Later that year he joined the Commerce Department, then led by Secretary Malcolm Baldrige, a former manufacturing executive. As undersecretary for international trade, Mr. Smart represented the United States in negotiations with Japan and Europe, among other trading partners, and before the General Agreement on Tariffs and Trade, a predecessor to the World Trade Organization.

He also helped lead an interagency “strike force” to counter what the Reagan administration considered unfair trade practices by foreign nations.

“Trade is a huge force for peace,” Mr. Smart once wrote. “No one wants to go to war against his customer or his supplier.” (Douglas Lees)

“There is no question that if you’re a tabby cat and say, ‘Please don’t do it, that’s unfair,’ you won’t get anywhere,” Mr. Smart told the New York Times in 1986. “On the other hand,” he continued, “if you confront these guys too much, they will say with some justification, ‘Politically, we can’t afford to do what you want because it will be perceived by our voters as rolling over and bowing to the Yankee imperialist.’ The fine line is somewhere between no pressure and too much pressure.”

After Baldrige died in a rodeo accident in 1987, Mr. Smart served briefly as acting commerce secretary. He left government in 1988, when he was passed over by Baldrige’s successor, C. William Verity Jr., for the No. 2 role at the agency.

He remained active in trade issues for decades after and in recent years called on Congress to support the Trans-Pacific Partnership, a trade agreement pushed by the Obama administration and from which President Trump later withdrew.

“Trade is a huge force for peace,” Mr. Smart wrote in a letter to the editor published in The Washington Post in 2015. “We become friendly partners with fellow trading nations. We talk, we bargain, we respect each other. No one wants to go to war against his customer or his supplier.”

Stephen Bruce Smart Jr. was born in New York City on Feb. 7, 1923, and grew up in Bedford, N.Y. His father was president and chairman of the Fruit of the Loom clothing company.

Mr. Smart received a bachelor’s degree in engineering from Harvard University in 1945 and a master’s degree in civil engineering from the Massachusetts Institute of Technology in 1947. He served in the Army during World War II and the Korean War.

After his government service, he was a senior fellow with the World Resources Institute, a Washington-based environmental research organization. He also was a board vice chairman at the Nature Conservancy and wrote the volume “Beyond Compliance: A New Industry View of the Environment” (1992).

An equine enthusiast, he ran a horse and cattle farm in Upperville, Va., and wrote several books about horses as well as a memoir, “Indian Summer,” co-authored with his wife of 69 years, the former Edith Merrill.

Besides his wife, of Middleburg, survivors include four children, Edith Moore of Scottsdale, Ariz., William Smart of Bainbridge Island, Wash., Charlotte Rogan of Westport, Conn., and Priscilla Schwarzenbach of Marblehead, Mass.; a sister; 11 grandchildren; and 13 great-grandchildren.