When Joseph Weisberg was training to be a case officer for the C.I.A. in the early 1990s, he soon learned that deception was a crucial skill, one that involved lying to his family on a regular basis.

“It was painful,” Mr. Weisberg recalled. “Fundamentally, lies were at the core of the relationships. I lied to all my friends and most of the people in my family. I lied every day. I told 20 lies a day and I got used to it. It was hard for about two weeks. Then it got easy. I watched it happen to all of us.”

So does he find it easy to tell lies now? “It’s had the opposite effect,” he said.

That experience, though, has been put to good use in the critically acclaimed FX show “The Americans,” of which Mr. Weisberg, 47, is the creator and head writer.

The show, which is shown on Wednesday nights, tells the story of two Russian spies, Elizabeth and Philip Jennings, living undercover in suburban Virginia in the 1980s, at the height of the Reagan-era cold war. Their artful deceptions — a pretend marriage, made-up back stories, ever-changing identities, quick-shifting loyalties — are at the series’ core.