His smile can light up the screen, but he keeps that in reserve. Approaching the age of 40, Matt Damon still looks as fresh-faced as he did when he first drew wide attention for his supporting role in Edward Zwick's Courage Under Fire, released in 1996. He conveyed great admiration for a certain character, even while suggesting a layer of doubt that hid below the surface. It was a fine role, but it wasn't his best.
He made a big splash the following year as a young lawyer in Francis Coppola's adaptation of John Grisham's The Rainmaker, and as a genius with issues in Gus Van Sant's Good Will Hunting. The latter, based on a script that he wrote with his good pal Ben Affleck, provided him with a showcase dreamed of by all actors, and earned him an Academy Award nomination. (He and Affleck won, instead, for their screenplay.) The two parts established him as a leading man -- he demonstrated confidence, charm, and a measure of vulnerability -- but they weren't his best roles.
He teamed with Ed Norton in John Dahl's Rounders, and was overshadowed in the process, before taking a major stride forward with Anthony Minghella's The Talented Mr. Ripley. Damon came very close to capturing the elusive essence of the titular character, created by Patricia Highsmith, leaving behind the trail of a haunted, demented man. Damon was very, very good, and it was his best role up to that date. But he's done better since then.