Complex sentence: His career was launched with the success of the film "Good Will Hunting" (1997) that he wrote with his friend and fellow actor Ben Affleck and which won them Academy and Golden Globe Awards for Best Screenplay.
Split into simpler sentences: His career was launched with the success of the film "Good Will Hunting" (1997). Damon and his friend and fellow actor Ben Affleck co-wrote the screenplay, for which they won Academy and Golden Globe Awards for Best Screenplay.