Finding the right person to adapt The Graduate from Charles Webb's book wasn't easy. An early attempt with the playwright William Hanley fizzled out, and the next screenwriter, Calder Willingham, turned in a script that no one liked (partly because Willingham himself had no enthusiasm for Webb's source material). Finally, Lawrence Turman settled on Buck Henry, a young improv comic and a writer for the TV spy comedy, Get Smart. Fortunately, as Henry noted, he felt the same about main character Benjamin Braddock as Turman and the director Mike Nichols did: they all related.
According to Nichols, the script was really all Henry's work, although Willingham sued for credit, which he received. Much of the dialogue came directly out of Webb's book, but Henry did make changes, including one famous contribution, the movie's most iconic line. He was totally responsible for the now-storied, "Just one word… Plastics" exchange, in which an older family friend gives Benjamin some unsolicited and fantastically dull career advice. (Henry also plays the role of the room clerk who manages to accidentally disconcert Benjamin by asking him if he's at the hotel "for an affair," meaning a party.) (Source)
Henry's script helped transform The Graduate from a fairly unsuccessful book into a cinema classic. And it launched his career to new heights as well (as penning the script for one of the most famous movies of all time might have a tendency to do). He went on to work on screenplays like Catch-22 (another movie with '60s counterculture import), Heaven Can Wait (which captures his comic style, like The Graduate), and Grumpy Old Men. He had a successful TV and film acting career and directed a few films as well, not to mention hosting Saturday Night Live ten times. (Source)
Not a bad resume.