Siberry was born in
Hobart,
Tasmania, Australia. He graduated from the
National Institute of Dramatic Art in
Sydney, Australia and began his career in
Adelaide at the
State Theatre Company of South Australia before moving to England to perform for the
Royal Shakespeare Company. On
Broadway, Siberry has performed the likes of Nicholas Nickleby in
The Life and Adventures of Nicholas Nickleby, Gratiano in
The Merchant of Venice, Captain Georg von Trapp in
The Sound of Music and Shakespeare in
The Frogs (
Lincoln Center). Other theatre credits include Morrell in
Candida and Astrov in
Uncle Vanya at the
McCarter Theatre in Princeton, New Jersey and Osbourne in ''
Journey's End, Oberon in A Midsummer Night's Dream and Billy Flynn in Chicago'' at London's
West end theatre. He portrayed
King Arthur in the U.S. National Tour of ''
Monty Python's Spamalot'' for two years before reprising it on Broadway in 2008. In 2017, he performed as Leo Tresler in the Tony-nominated Broadway drama
Junk at the Lincoln Center. His notable television appearances include
Strangers and Brothers,
Sherlock Holmes;
Jeeves and Wooster;
Highlander;
The Grand;
Silent Witness;
Victoria & Albert;
House of Cards;
Boardwalk Empire;
The Blacklist;
Jessica Jones;
Madam Secretary;
The Last Tycoon;
Severance; and
The Society. He had supporting roles in the films
Boundaries of the Heart,
Teen Agent, and
Birdman. ==Filmography==