Jim Carter serves ‘Downton Abbey’ as its beloved butler

Among the superb cast, a similarly towering figure is Jim Carter, who plays him.

Bringing him to life is an actor who makes Carson’s crustiness heroic, his unwavering sense of duty lovable to the viewer.

With “Downton” returning for its sixth and final season (Sunday, Jan. 3, at 9 p.m. on PBS), Mr. Carson’s humanness will be exposed more than ever as his torturously arm’s-length courtship of housekeeper Mrs. Hughes (played by Phyllis Logan) finally blossoms.

What happens, including an unlikely interlude in this first episode “which hopefully will melt hearts across the country,” is only one among many resolutions as the series comes in for a landing in the mid-1920s.

Viewers have awaited these and other answers from a costume drama that, since its U.S. debut five years ago, has reigned as a lavish and literate phenomenon.

For the British-born Carter, 67, the road to “Downton” began long ago when he dropped out of law studies at the University of Sussex and joined a fringe theater troupe he equates with “a door to the promised land.”

Stage, film and TV jobs followed in a career that has kept him busy and happy, enjoying each role free from worry over how the finished product might fare with critics or the public.

Julian Fellowes, who created “Downton Abbey” and wrote every episode, knows it’s funny when my character says things like, ‘A maid in the dining room with a duke?

When we wrapped, the other actors were getting weepy, and I thought, ‘C’mon!’ But then the producers came out and thanked them, and I thought, ‘We’ve got to thank the crew, too, because they’ve been with us every inch of the way.’