Keri Russell still has that great hair, but as the deadly Soviet spy Elizabeth Jennings on “The Americans” she is a long way from the shy college coed she played on “Felicity” a decade and a half ago. Unlike either of the tightly wound characters, though, Russell is loose and personable.

The now 37-year-old actress does have something in common with Elizabeth, as she is the mother of two. Russell’s children are 6 and 2, younger than her TV children, 14-year-old Paige (Holly Taylor) and 11-year-old Henry (Keidrich Sellati).

“What’s fun about the show is that Elizabeth goes on all these spy missions, and then she’s in the car flipping out like a normal mom about something that her 14-year-old girl is doing,” Russell said.

That strange dynamic has made FX’s “The Americans” both a hit with fans and a critical success, with two Emmy nominations as well as being named the best new program by the Television Critics Association.

As the series enters its second season on Wednesday, it’s 1981 and Elizabeth and her husband, Philip (Matthew Rhys) — KGB sleeper agents for 15 years posing as travel agents in the Washington, D.C., area — have barely escaped being caught in an FBI trap, leaving Elizabeth with a gunshot wound.

But it isn’t long before the couple are once again juggling their parental duties with espionage assignments involving assassinations, sex and disguises.

“If last year was a metaphor on marriage, this year is a metaphor on family,” Russell says. “Philip and Elizabeth start the season with a new kind of unified front with each other. Certainly Elizabeth hasn’t been engaged emotionally before, and I think she has decided this is where she wants to be.”

When we met the Jenningses in the first season, it was a sham marriage, but circumstances forced them to look at the value of the life they built together and weigh it against their allegiance to Mother Russia.

The series — set during the Cold War tensions of Reagan’s America — was conceived by former CIA officer Joe Weisberg, who was inspired by true stories of Soviet and Russian sleeper agents. (In 2010, a network of Russian sleeper agents was arrested in the U.S.)

Russell was pretty young during the Cold War.

“I mostly remember the America of the ’80s, like the songs of Bruce Springsteen,” she says. “And I definitely remember the bad guys in all the films being either Russian or East German.”

By the time she was 15 in the early 1990s, Russell was a cast member of Disney Channel’s “All New Mickey Mouse Club,” and after various TV and film roles became a celebrity when J.J. Abrams’ “Felicity” became a hit in 1998.

After the series ended, the actress took a year off. With more than a decade of acting at a young age, she wanted some breathing space.

“I had saved enough money to rent an apartment in New York,” she recounts. “I got to show up at my girlfriends’ birthday parties, got to go dancing and walk home in the snow. That saved me. I got interested in things, got to read books again and very slowly started working my way back to acting.”

But, Russell adds, she might not have come back had it been like it is now with “all this extraneous stuff like clothing — especially for a girl — and press stuff.” (On this day, Russell looks pretty comfortable in white jeans and a black leather jacket.)

Undoubtedly, the success of “The Americans” has brought numerous press demands.

Adding to this is the announcement by the actress in early December that she had split from her husband of nearly seven years. Soon after that, she and Rhys were linked romantically, although the pair aren’t talking about that.

In the February issue of GQ magazine, Russell and Rhys are seen in a photo shoot of sexy poses where she is in black lingerie. FX’s TV promo for the new season provocatively showing the pair in various positions in bed has also prompted media attention. A TCA press conference after this interview with Russell was filled with numerous questions about the sex on the show.

That, of course, is the tricky part of the premise for “The Americans.” No matter how much Elizabeth and Philip come across as loving parents, they are schooled in deception and are willing to do anything for their country, including kill and have sex with other people.

In the first episode of the new season, Elizabeth is the bait in a “honey trap” sprung on an employee of Lockheed Martin’s famed Skunk Works, which developed top-secret aircraft, technology the Soviet Union would have likely tried to get its hands on in the 1980s. (During the Cold War, the famed facility was located in Burbank.)

Meanwhile, Philip has a violent encounter with Afghan freedom fighters looking for funding in the United States. Remember, the Soviets had invaded the Middle Eastern country. The show, indeed, does its homework beyond just getting the authentic Jordache jeans Elizabeth wears.

It’s been fun for Russell to play Elizabeth in her many disguises, although occasionally knowing who she is day to day can be confusing.

“With constant shifting relationships, sometimes we have to go in a room and sort it out,” she says. “That’s what’s so interesting and keeps driving me. And Matthew is such a great partner — he is so skilled and has such a big emotional range.”

Russell, who plans to “make cupcakes and do school drop-offs” when shooting for the show finishes, is intrigued by an arc this season in which Elizabeth has trouble dealing with teenage Paige. (“She’s wearing lipstick all of a sudden.”) I mention to Russell that she has a few years to go before she has to worry about that sort of thing herself.

“I was a teenager and I can imagine what’s in store,” she responds.

“I can’t imagine you were that bad,” I reply.

“You’d be surprised. You’d be surprised,” she says, nodding with a sly smile.