Margo Martindale

If there was one performance that earned almost unanimous praise from both TV critics and  viewers alike this season, it was that of Justified's Margo Martindale. So the fact that her riveting portrayal of Harlan County crime family matriarch Mags Bennett earned the stage and screen veteran her first Emmy nomination is, well, justified.

Check out our complete Emmys coverage

"I'm truly beside myself with joy," Martindale tells TVGuide.com, giddy with laughter. "It's a whole new world for me. I've been nominated for a Tony, but this whole thing is just joyous."

Although Martindale says she never anticipated the waves of support and critical appreciation she received throughout the season, she instantly responded to Mags on the page. "I knew it was a magnificent character from the first thing I read," she said. "The beauty of the writing — it was just so poetic. Those types of parts don't come along. I knew it was special, but I certainly didn't know it could go to the heights that it did."

Executive producer Graham Yost was the man responsible for taking the character to such heights. "We saw that first episode, and the scene where she poisons Walt McCreedy," Yost recalls. "We looked at each other and said, 'Well, we've got a season.' She was just so utterly terrifying yet human and believable. And the next thought was just us rubbing our hands with glee, thinking, 'OK, what else can we do with her?'"

Exclusive: What's next for Justified? Our burning questions answered

The better question would have been what couldn't the show do with Mags. Martindale transitioned effortlessly between gleeful Southern hospitality and unnerving menace, often in the same scene. Ultimately, however, after losing two of her sons, Mags takes her own life, drinking the same poisoned "apple pie" moonshine she'd used on others.

Martindale says she cried when she first read Mags' suicide and was an emotional mess on the day it was shot. But she thinks the ending was right. "It's better to go out with a bang than a whimper," she says. "Did I want it to go longer? Would I have loved to be a part of that show until it ran out? Absolutely. Did I think it was perfect? I thought it was. They stuck with their artistic muse to end it that way."

Also giving heaps of credit to Martindale was co-star Walton Goggins, who, along with series star Timothy Olyphant and guest star Jeremy Davies, also earned a nod on Thursday. "I've been a fan of Margo's for years," Goggins says. "To sit across from this woman — and for my mouth to be open with wonderment at every single take that she did — was a highlight of my career. I'm just overwhelmed with gratitude."

Check out photos of the Justified cast

Goggins, who was overlooked by the Academy for his masterful work on The Shield, says he can't believe his own dumb luck to play a character like Justified's Boyd Crowder, a career criminal who found faith, only to return to his wicked ways. After all, Boyd was originally supposed to die in the pilot, which was based on an Elmore Leonard short story.

"We had an opportunity that was limitless. There were no parameters as to who this person could be," Goggins says. "We've been able to go forward with this guy in ways that still surprise me. With every single script, every single scene and every single word, it's a discovery. It's the opportunity of a lifetime, and I didn't think I would ever get it after playing Shane Vendrell."

While Yost and Goggins will get to continue spinning adventures for Boyd, Raylan (Olyphant) and the rest of the gang, Martindale is moving on to CBS' A Gifted Man, where she will play the assistant of Patrick Wilson's lead character, a surgeon who begins seeing his dead ex-wife.

Get more of today's latest news

What drew Martindale to the role? "I liked putting on pretty clothes and wearing some makeup," she says with a laugh, joking about Mags' warts-and-all simplicity. But seriously — and perhaps most importantly for viewers — Martindale says she hopes this Emmy nomination opens up more doors for her. Because she's just getting warmed up.

"I haven't gotten to do all the things I can do," she says. "Mags Bennett is alive and well inside me at all times, even if she's gone."