Greek composer. Although largely self-taught, he was active internationally. Due to the impact of World War II and the subsequent civil war, Greek composers of the time tended to be isolated from global trends. Amidst this, Hadjidakis made broad contributions to the promotion of Greek music. His contributions included:

• Re-evaluating "Rebetiko," a genre of Greek popular song that had been dismissed as merely popular.
• Organizing lectures in Athens on composers active in America, such as Menotti and Copland.
• Holding a competition named after himself at the National Technical University of Athens, introducing works by Greek composers active abroad, such as Xenakis.
• Conducting an experimental orchestral ensemble he founded in Athens, premiering works by Greek composers.
• Serving in various capacities, including Deputy General Director of the Greek National Opera, Head of Radio Program Production, and Lifetime General Director of the Athens State Orchestra.

He composed numerous works for Greek cinema, the National Theatre, and other institutions. Among these, he received an Oscar for the theme song of Never on Sunday, which instantly brought Hadjidakis international recognition.