The British actor is riding high in Hollywood after his series about the war on terror became one of the most talked about dramas on TV and a personal favourite of Barack Obama.
On Sunday, Damian, who was the president's guest at a White House gala for the Camerons, beat hotly tipped contenders, Jon Hamm of Mad Men and Breaking Bad's Bryan Cranston.
CLICK ON PHOTOS FOR FULL GALLERY
Another Great Briton Dame Maggie Smith was also celebrating – albeit in absentia – as she snagged an Emmy for her role as Downton Abbey's snooty matriarch.
In his acceptance speech, Damian apologised to his US colleagues for being "one of those pesky Brits".
The 41-year-old went on to say: "I don't really believe in judging art, but I thought I'd show up just in case."
"What an extraordinary honour to be in a category with these golden actors setting a gold standard in acting in a golden age of TV.
"The cast that I work with who are delightful and enjoyable to dine with but especially to the two ladies who've suffered me the most, Claire Danes and Morena Baccarin. You're both beautiful and it's enjoyable working with you, every minute of it."
He also had a special mention for his wife, telling her: "The biggest thank you of all (goes) to the leading lady of my life Helen McCrory, I adore you darling, thank you for being here".
"My two children at home thought daddy had been nominated for an Emma. Well, Manon and Gulliver, Daddy just won an Emma."
Afterwards at a press conference with his pregnant co-star Claire, who was radiant in canary yellow Lanvin, he joked: "We're going to go away to a romantic island together, just for the weekend.
"When that baby is a ginger, you guys are going to have a field day."
Not that her man Hugh Dancy would have minded his cheeky quips. Claire paid an emotional tribute to Hugh, also a Brit, telling him: "My husband, my love, my life, my baby daddy.
"I couldn't do anything without you. I love you so much and I am so grateful."
Elsewhere the cast of Modern Family was having a ball after bagging the prize for best comedy for the third year in a row.
The entire audience got to their feet when Michael J Fox arrived on stage to present the award.
Respected in the business for continuing to work, despite suffering from Parkinson's, the popular actor quipped: "Steady as a rock."
Beautiful as ever in a sequinned teal number with sexy cut outs, Modern Family's Sofia Vergara seemed to be having particular fun as she cuddled up to her fiancé Nick Loeb and son Manolo Gonalez.
Other glamorous duos at the awards included Nicole Kidman and her husband Keith Urban, looking as in love as ever after six years.
And no wonder since the Australian actress, who said she'll be in trouble with the director of her Grace Kelly biopic for getting a suntan, was a vision in a sequinned white column by Antonio Berardi.
In a night of triumphs there were also plenty of laughs, most notably when talk show host Jon Stewart was tackled to the ground by his rivals Stephen Colbert and Jimmy Fallon.
2012 Emmy Award Winners
- Outstanding Drama Series
- Outstanding Lead Actress in a Drama Series
Clare Danes in Homeland
- Outstanding Lead Actor in a Drama Series
Damian Lewis in Homeland
- Supporting Actress
Maggie Smith in Downton Abbey
- Supporting Actor
Aaron Paul in Breaking Bad
- Miniseries or TV Movie
- Lead Actress in a Miniseries or Movie
Julianne Moore in Game Change
- Lead Actor in a Miniseries or Movie
Kevin Costner in Hatfields & McCoys
- Comedy Series
- Comedy Actor
Jon Cryer in Two and a Half Men
- Comedy Actress
Julia Louis-Dreyfus in Veep