RICHARD ARMITAGE IS known for his controlled and stoic performances, so it’s rather disconcerting—and funny—to get an excited and happy yelp out of the 43-year-old British actor.

“Ah, thank God, thank you, thank you,” he says with a deep laugh when told that his diverse roles over the years, from brooding John Thornton in “North & South,” the 2004 BBC dramatization of Elizabeth Gaskell’s novel, to British spy Lucas North in the TV series “Spooks,” to Thorin Oakenshield, leader of the dwarves in Peter Jackson’s “The Hobbit” trilogy, make it hard to typecast him—except, perhaps, as a heartthrob.

Born in Leicester, England, and an alum of the London Academy of Music and Dramatic Art, the New York-based actor has had a busy year. He received rave reviews in London over the summer for his spellbinding performance as the tormented John Proctor in the Old Vic’s production of Arthur Miller’s “The Crucible.” The production was so well-received, in fact, that it’s being screened in cinemas in the U.K. and Ireland next week, and other locations world-wide in February.

The actor was also on the silver screen this summer, in Steven Quale’s disaster movie “Into the Storm,” and he filmed “Urban Grimshaw and the Shed Crew,” which is currently in postproduction and co-stars Anna Friel. In October, he began work on “Sleepwalker” with director Elliott Lester—which Mr. Armitage says is a psychological thriller along the lines of “Memento” or the Italian film “La Doppia Ora”—and he will also be making a cameo appearance in a new film adaptation of Lewis Carroll’s second “Alice” book, “Through the Looking Glass,” alongside Johnny Depp and Anne Hathaway.

In December, Mr. Armitage—who at the age of 17 joined a circus in Budapest to get his actor’s Equity card—will be busy promoting “The Hobbit: The Battle of the Five Armies,” the last in the blockbuster trilogy, which premiered in London this week. “I know Peter has made an extraordinary film, because it is his last visit to Middle Earth—he will certainly do it justice,” says Mr. Armitage. “It will be a great way to end the year.”