Most of Simon's scripts contain humor rooted in the character's conflict: in general, two or more people who are antagonistic resolve their conflicts by the end. While this may sound formulaic (and to some extent it is), Simon also excels at creating fully-rounded three-dimensional characters. Actors not only enjoy playing the roles he creates, many end up winning awards for them. On stage, Walter Matthau, Dinah Manoff, Matthew Broderick, Kevin Spacey and Mercedes Ruehl, to name a few, have received Tony Awards. Hume Cronyn received an Emmy for "Neil Simon's 'Broadway Bound'" and among those who have won Oscars are George Burns, Richard Dreyfuss and Maggie Smith.

For many years, Simon's popular success seemed to overshadow his critical acceptance. Starting with the autobiographical trilogy, his work began to be perceived as richer and deeper The culmination was the 1991 Pulitzer Prize in Drama for "Lost in Yonkers". After returning to the world of "Your Show of Shows" for a Broadway production of "Laughter on the 23rd Floor" (1993), he cited the high cost of producing plays on the Great White Way, controversially insisting that "London Suite" be produced Off-Broadway in 1994. In 1997, Simon's 30th play, "Proposals", featuring his first major black character, opened on Broadway but quickly closed, while a revival of "The Sunshine Boys" enjoyed a much longer run thanks to the popularity of its stars Tony Randall and Jack Klugman.

Simon's feature output in the 90s fell off following the box-office failure of "The Marrying Man" (1991) and "Neil Simon's 'Lost in Yonkers'" (1993), causing the writer to turn to the small screen with "Neil Simon's 'London Suite'" (NBC, 1996), with a cast that included sitcom veterans Kelsey Grammer, Julia Louis-Dreyfuss and Richard Mulligan, and a misguided "The Sunshine Boys" (CBS, 1997), which was filmed in 1995 and teamed Peter Falk and Woody Allen. His return to the big screen with the sequel "The Odd Couple II" (1998) sank at the box office despite the presence of Matthau and Jack Lemmon . Later that year, a remake of "The-Out-of-Towners" (adapted by Marc Lawrence) starred Steve Martin and Goldie Hawn in the roles originated by Lemmon and Sandy Dennis.