Sometimes credited as: Henry Bookholt or Horst Bucholz, born in Berlin, he was the son of a shoemaker.

Buchholz landed his first stage role at 15 in a Berlin theater version of the German children's classic Emil and the Detectives. He dropped out of high school in 1950, took acting lessons and was cast in roles on Berlin stages over the next five years. His Broadway debut came in 1959 in Cherie.

Dubbed the James Dean of German films for the rebellious teens he played in the late 1950s, Buchholz moved to the United States and scored his first Hollywood hit with a role in The Magnificent Seven, the 1960 western with Yul Brynner, Steve McQueen and James Coburn.

The next year, director Billy Wilder cast him alongside James Cagney in One, Two, Three. Set around the building of the Berlin Wall, the biting comedy features Cagney as a Coca-Cola executive who learns his boss' daughter has secretly married a communist, played by Buchholz.

He also made movies in Britain, Spain, Italy and France, and played a Nazi concentration camp doctor in Roberto Benigni's Oscar-winning 1997 film Life is Beautiful.

He married Myriam Bru and had 1 son and 1 daughter. Buchholz, who was recovering from a broken thighbone, died of pneumonia in intensive care at the Charite hospital in Berlin.