Nicholas was born on 15th May, 1950 in Washington DC. His father Col Thomas W. Hammond and mother (actress Eileen Bennett) married in 1945 and already had one son, David (born in Paris in 1946).

When Nicholas was 6 years old the family moved to Europe. In 1959 his mother took him to see the musical "My Fair Lady" (with Julie Andrews) on stage in London. After seeing this show Nicholas decided he wanted to be an actor. The family returned to the US when Nicholas was 10 years old. He landed his first part (a small role in movie "The Lord of the Flies) short after that.

Nicholas appeared on Broadway and on television before he got the role of Friedrich in the hit movie "The Sound of Music".

Nicholas went Australia in the mid 80s for a private visit but also took some roles while he was there. After a year, he realized he liked living in Australia and decided to stay. He now has dual citizenship and lives in Sydney where he still works as an actor, screenwriter and director.