It's evident that the cast of Grease isn't the same age as the characters they're playing, so how old were Oliva Newton-John and John Travolta when they played Sandy Olsson and Danny Zuko? In 1978, Grease immediately rose to fame and became the highest-grossing musical film up to that point. Its powerful combination of energetic music, impressive choreography, and 1950s nostalgia made it an instant addition to the pop culture hall of fame, where it has stayed for more than four decades. Curiously, the chemistry between the main characters - Sandy and Danny - helped the audience overlook one major detail: the actors were far older than their hand-jiving teenage counterparts.
The age of the characters in Grease plays an important part in the movie, with the two cliques of students at Rydell High School experiencing the highs and lows of their senior year. The girls-only Pink Ladies gang loves pajama parties and goes crazy over Sandy's new lover, while the boys-only T-Birds greaser gang is crazy about cars, leather jackets, and girls (perhaps a little bit too much). This immaturity is why Grease sometimes gives terrible life advice and also why events like the school dance matter so much to the characters. Sometimes it's hard to look past how the 18-year-old Sonny was played by a 31-year old Michael Tucci, and how Rizzo, who was also supposed to be 18 in the movie, was played by a 33-year-old Stockard Channing.
Sandy and Danny look closer to their supposed age, but still, one of the things most people don't know about Grease is that Olivia Newton-John turned 29 while playing the 17-year-old Sandy Olsson. Meanwhile, the greaser boy she describes to the Pink Ladies as "he was sweet, just turned 18" actually was 23 when shooting the movie, with John Travolta no less than six years younger than his co-star while playing Danny Zuko. All the acrobatic dancing and the sheer fun these characters bring to the film make anyone forget those kids are really in their twenties and thirties, however, and the film barely suffers from it.
It's not like Grease was the first or the last movie to have have a cast far older than the characters they're playing. It's just that general audiences are becoming increasingly more aware of this motif, which is still as popular nowadays with shows like 13 Reasons Why casting older actors as teenagers. This is more of a convenient practice to every production rather than a recurring oversight, given that working with adults relieves the directors and producers from more complicated child labor laws and problems like the actors growing too fast. For Grease, it meant having an incredibly talented cast that turned the movie into a classic.
Grease has become such a beloved piece of cinema that the older-looking cast is normally seen as a distinctive feature instead of a flaw. The 1982 sequel went completely under the radar, but the original's legacy is still as strong as ever. In 2019, Paramount was looking to make a Grease prequel called Summer Loving, and a spinoff called Rydell High is coming to HBO Max. Whether age-accurate or older-looking, hopes are high for the new cast to be the one the fans want.