Although this film is nowadays viewed as a cult classic, European critics at the Cannes Film Festival were so hostile to the film that director John Frankenheimer refused to leave nearby Monte Carlo, where he was shooting Grand Prix (1966), for the press conference. Rock Hudson was sent instead and was unable to answer the critical questions during the hostile session.

"Seconds" has gained a cult status in later years and is frequently revived. According to director John Frankenheimer it's "the only movie, really, that's ever gone from failure to classic without ever having been a success."

Initially director John Frankenheimer was reluctant to cast Hudson, who he felt was a lightweight actor in comparison to Laurence Olivier and Kirk Douglas, other actors he wanted for the lead part. It was only after Hudson's agent convinced him at a party that Hudson could do the role that he went ahead with Hudson. He has later gone on to praise Hudson's work in the film and felt he was impeccably cast.

This was John Randolph's first film in fifteen years (since an uncredited one-day bit part in Fourteen Hours (1951)). He had been blacklisted for his radical sympathies in the early '50s, and his wife Sara Cunningham later said that he had been on the blacklist longer than any other actor. Two other actors in prominent roles, Jeff Corey and Nedrick Young, were also long blacklisted.

Beach Boys composer Brian Wilson saw the movie in a theater during its first run. Overworked and showing signs of a breakdown, Wilson both liked the theme of the movie (changing identities and starting over), and found its downside disturbing. He wondered later if musical rival Phil Spector had somehow convinced Columbia Pictures to produce the movie, just "to mess with my mind".

In order to shoot in Grand Central Station without attracting too much attention, Frankenheimer hired a male model and a Playboy bunny to make-out on the stairs while being filmed by a fake crew. This distraction allowed the real crew to shoot with a camera in a suitcase.

According to John Frankenheimer, it was Hudson's idea to have two different actors play the Arthur Hamilton/Tony Wilson role, instead of having just one actor play both parts with makeup changes like originally envisioned. Hudson felt that he would be unconvincing as Arthur Hamilton and said he would only do the movie in the Tony Wilson role. Frankenheimer agreed and felt the film was much stronger as a result of the change.

The depiction of Hamilton's plastic surgery includes several shots of an actual rhinoplasty operation. Director John Frankenheimer made several of these shots himself after the cameraman fainted.

Rock Hudson was five inches taller than his "older self" John Randolph. This was worked around with a careful choice of camera angles. Randolph and Hudson also spent casual time together in the days before shooting, so Hudson could learn to copy Randolph's mannerisms.

A scene in which Arthur Hamilton as Antiochus Wilson visits his daughter and her husband was shot, but ultimately cut from the film. The daughter was played by Evans Evans while her husband was played by Leonard Nimoy.

Rock Hudson got drunk for real for the scene in which he gets drunk at a party.

The house that is provided for Rock Hudson's character was owned by director John Frankenheimer. It was later sold.

Arthur Hamilton's tennis trophy in reality belonged to John Frankenheimer.

While choosing films in Criterion, filmmaker Gaspar Noé's first pick was this movie, even stating that he would remake it someday.

John Randolph had to learn how to do many things with his left hand because Rock Hudson was left-handed.

Director John Frankenheimer once attested that the initial lack of success was due to the fact that there wasn't any real audience for the picture. He said those who wanted to see a Rock Hudson film didn't want to see him in this kind of film and those who liked dark science fiction and morality plays weren't interested in seeing a movie with Rock Hudson in it, leaving about an "audience on 6 people" remaining.

Rehearsals were done for two weeks prior to the principal shooting of this film.

On assignment, professed Frankenheimer admirer Roger Avary wrote a remake titled 2NDS for director Jonathan Mostow. It was eventually canceled.

Nora's house is one in which John Frankenheimer formerly rented and lived.

The mounted fish over Arthur's mantle belonged to John Frankenheimer.

When Seconds was released actress Frances Reid had already been appearing for close to year on Days of Our Lives as beloved matriarch Alice Horton. A role she became very famous for and portrayed for 45 years until her death in 2010.

Although Rock Hudson is top billing, he appears on screen only after 40 minutes of running time because the character he plays has quite different face and look after being transformed by a physical reconstruction surgery. John Randolph was chosen to play the scenes of the beginning before the physical reconstruction surgery.

Khigh Dhiegh (Davalo) also appeared in director John Frankenheimer's film The Manchurian Candidate four years earlier as Dr. Den Lo.

After making " Seven Days in May" , Kirk Douglas bought the rights and planned to re team with producer Edward Lewis and director John Frankenheimer.

Included among the "1001 Movies You Must See Before You Die", edited by Steven Schneider.

French censorship certificate: -13.