When militant radicals seized the U.S. Embassy in Iran in November 1979, they intended to take all its employees hostage. But five were elsewhere in the embassy compound and escaped capture. After six tense days of furtively moving around Tehran, one of them, Robert Anders, placed a call to a Canadian diplomat with whom he played tennis, and asked for help.

“Hell, yes, of course,” the diplomat, John Sheardown, answered. “Count on us.”

The five employees had by then been joined by a sixth. Four ended up being hidden for nearly three months in the home of Sheardown, the Canadian Embassy’s No. 2 official, who died Sunday at 88. The other two found refuge with the Canadian ambassador, Ken Taylor.

The episode, which came to be known as the “Canadian caper,” was a footnote to the Iranian hostage crisis, in which young Iranian revolutionaries seized the U.S. Embassy and held 52 people hostage for 444 days to try to force the U.S. to return the deposed shah from New York, where he was being treated for cancer. After the shah died in July 1980 in Egypt and war erupted between Iran and Iraq, negotiations with the U.S. led to the release of the hostages in January 1981.

The concealment and extrication of the U.S. diplomats by the Canadian government and the CIA inspired the recent movie “Argo.” Though Sheardown is not mentioned in it — public recognition always gravitated to Taylor, who is portrayed in the film as a hero — his role was nevertheless consequential.

“Without his enthusiastic welcome, we might have tried to survive on our own a few more days,” Mark Lijek, a retired Foreign Service officer, wrote in Slate last year. “We would have failed.”

Sheardown’s avuncular, pipe-puffing manner led his houseguests to call him Big Daddy. He bought groceries at different stores to disguise his household’s suddenly larger appetite. He bribed the garbage collector with money and beer for the same reason. Surveillance, including tanks at the end of the street, was constant. Strangers knocked on the front door, suspicious calls were commonplace, their car was repeatedly searched.

“We were already living in danger,” Sheardown’s wife, Zena, said in an interview Wednesday. “And certainly the danger was compounded because we were hiding, literally hiding, fugitives.”

Sheardown, she said, died in Ottawa, Ontario, where he lived, after being treated for Alzheimer’s disease and other ailments.

Sheardown was born on Oct. 11, 1924, in Sandwich, Ontario, a small town absorbed by Windsor in the 1930s. At 18, he joined the Canadian Air Force and flew a bomber in World War II, once crash-landing near an English village after limping back from an attack on Germany. He broke both legs, but was able to crawl to a pub door at 3 a.m. and rouse the owner. He asked for a glass of Scotch, which the owner gave him. The owner then asked for payment while Sheardown waited for an ambulance — a story Sheardown relished.

He joined Canada’s immigration service in the early 1960s and later transferred to the Foreign Service, where he specialized in immigration matters. He was busy in Tehran with Iranians who wanted to leave the country, as well as with Afghans who had fled their country after the Soviet Union invaded it in December 1979. His houseguests became an official part of his responsibilities after the Canadian Parliament held its first secret session since World War II to approve the rescue mission, which included issuing the Americans fake Canadian passports.

While in Tehran, the Americans in his rented 20-room house occupied themselves by listening to news on a shortwave radio, reading, playing Scrabble and cards and, by their own admission, drinking copiously. They had to leave the house only once, when the owner had a real estate agent show it to a potential buyer. The two Americans staying with Taylor were spirited to the Sheardown house for Thanksgiving and Christmas.

The diplomats posed as members of a film crew who had supposedly been scouting locations. They had been taught how to speak like Canadians — for instance, by ending sentences with “eh?”