The character of Susan Johnson was not played by Jill Eikenberry who had portrayed the character in Arthur (1981). This was because Eikenberry was at the time unavailable due to being contracted to L.A. Law (1986), playing Ann Kelsey. Because of this, the part of Susan Johnson in this movie was played by Cynthia Sikes instead. The movie even pokes fun at this in a scene where Arthur remarks at how much taller Susan has gotten since the last time he saw her.
Dudley Moore has been said to have based his characterization of Arthur partly on Peter Cook, whose excessive drinking had soured his and Moore's comedic partnership in the 1970s.
Screenwriter Andy Breckman was allegedly disappointed by the movie and went to his hometown theater just to hang around and apologize to the people who went to see it.
Dudley Moore is seen playing the piano in this movie. In real-life, Moore was a pianist. On movie sets, Moore would often entertain the crew by playing the piano between breaks in filming.