One of Riley's most famous moments came when he guaranteed the crowd a repeat championship during the Lakers' championship parade in downtown Los Angeles (he first made the guarantee during the post-victory locker room celebration). While the 1988 Lakers did not produce as many wins in the regular season as the 1987 Lakers, they still won the NBA title, becoming the first team in 19 years to repeat as champions. The Lakers beat the Detroit Pistons in seven games in the 1988 NBA Finals, making good on Riley's promise. Riley's titles with the Lakers make him one of six men to play for an NBA Championship team and later coach the same NBA team to a championship; the others are George Senesky, Bill Russell, Tom Heinsohn, K. C. Jones and Billy Cunningham.
In 1988, Riley published a book entitled Showtime: Inside the Lakers' Breakthrough Season, a New York Times best seller which recapped the Lakers' successful run to the 1987 NBA Championship. One of the phrases Riley coined in the book was the "Disease of More", stating that "success is often the first step toward disaster" and that defending champions often fail the following season because every player who returns wants more playing time, more shots per game, and more money. The phrase stemmed from the Lakers' disappointing 1980–81 campaign coming off a championship the previous season.