Mike Reid was fired as Sir Roger Moore's underwater stunt double after making fun of the actor's thinning hair.

Early episodes included the gimmick of having Sir Roger Moore speak directly to the audience. Later, this was replaced by narration. In one early episode, an old woman guesses Templar's name. She says his name must be James Bond. Sir Roger Moore, of course, went on to play James Bond 007.

In order to give the Simon Templar character a more 1940s look, Sir Roger Moore wore a hairpiece.

The very distinctive melody of the show's theme was composed by Leslie Charteris, the writer who created Simon Templar for his series of novels.

Sir Roger Moore said that when filming scenes that were supposed to be in countries where they drove on the other side of the road, they would simply flip the film in the camera.

Amongst the actors offered the role of Simon Templar was Patrick McGoohan. McGoohan turned down the role owing to his disapproval of Simon Templar's womanizing (he also turned down James Bond in "Dr. No (1962)" for much of the same reason).

Sir Roger Moore wore lifts and a hairpiece to play Simon Templar.

During the writing of his manuscripts, Leslie Charteris constantly designated Simon Templar by his initials (S.T.) in order to save time. That's how the idea came up to give him the nickname "the Saint".

A version of the car story seen elsewhere says that Jaguar were indeed requested to supply the (then new) E type as an ideal "typically British" steed for Simon Templar, also typically British in the early sixties, Jaguar were bedeviled with strikes and parts supply, and could not deliver on time. Commencement date was looming, and finally Sir Roger Moore volunteered his personal car, the now famed Volvo P1800. Although stylish, it was hardly the racy image needed (post-production gave it the exciting exhaust note). For Volvo, it was a godsend. The P1800 had been selling sluggishly in the UK, suddenly it was "cool", and sales skyrocketed, and as a result, production was extended past the formerly planned finish date. On the rare occasions the vehicle was actually on-location on real streets, it was technically illegal, as the "ST 1" licence plate was registered to another vehicle (the cops turned a blind eye).

Whilst putting the series together, it was decided to make the Simon Templar character more likeable than in the stories and far less violent.

Leslie Charteris guarded the rights to his creation closely, and earlier attempts to televise his stories had come to nothing. Producers Robert S. Baker and Monty Berman were recommended by John Paddy Carstairs, who had befriended the writer while directing The Saint in London (1939) (and who would direct The Saint: The Arrow of God (1962) and The Saint: The Romantic Matron (1963) for this run); Lew Grade proposed a budget of £30,000 per episode, which also helped convince Charteris that Templar was in safe hands.

The series was sold to sixty-three countries, and garnered over £350 million in profits.

When directing episodes, Sir Roger Moore said that he liked to sketch how he wanted each scene to begin and end, and let the actors and actresses fill in the rest.

Out of all of the one hour programs from ITC, this show holds the record for producing the highest number of episodes. The total is one hundred eighteen.

Leslie Charteris originally wanted David Niven to star as Simon Templar.

Sir Roger Moore was originally told that the series was going to be a half hour. It wasn't until they held a press conference to announce the series that he found out it was going to be a one hour series.

Nine episodes were directed by Sir Roger Moore. These were: The Saint: Sophia (1964), The Saint: The Miracle Tea Party (1964), The Saint: The Contract (1965), The Saint: The Man Who Could Not Die (1965), The Saint: The Old Treasure Story (1965), The Saint: Escape Route (1966), The Saint: Invitation to Danger (1968), The Saint: The House on Dragon's Rock (1966), and The Saint: Where the Money Is (1968).

Leslie Charteris proved to be decidedly vocal, regarding his various criticisms with the series.

Simon Templar in the series differed from that of the books. The character of the original stories had a more hard edge and had no qualms about committing murder. Therefore, as written in the series, Templar had to be made more likable and less inclined to kill.

The series started in syndication in the U.S. However, it was later picked up by NBC.

In order to save on productions costs, British locations were substituted for some of the exotic locations.

The producers of the show went to Jaguar to ask for a free car, in return for the publicity that would follow a successful television series. Jaguar refused, so the producers went to Volvo which was more than happy to risk one P1800S coupe, and the publicity, as it turned out, far outweighed the value of the car.

Though filmed in England, many of the episodes feature cars sometimes with right-hand drive and other times with left-hand drive depending on the locale of the story.

From 1966 onwards, there were various episodes that featured some rather fanciful storylines. The following examples: "The Convenient Monster", "The House on Dragon's Rock", and "The Power Artists" are testaments to this.

For the black-and-white part of the series, Sir Roger Moore would usually begin by talking to the camera as though addressing the viewers. Later on, when the show went to color, Moore recorded a different voice-over for each episode.

Many actors would make return appearances during the time the series was in production. These included Patrick Troughton, Peter Wyngarde, Eddie Byrne, Justine Lord, Annette Andre, Jean Marsh, John Bennett and Mike Pratt.

Leslie Charteris always expected the writers of the series to reveal how Simon Templar secured his wealth and could live independently. According to Charteris, it was never explained.

In a foreshadowing of things to come, Lois Maxwell, who played Miss Moneypenny in the James Bond film franchise, made two guest spots. Maxwell and Sir Roger Moore were classmates at R.A.D.A.

Sir Roger Moore recalled that Mia Farrow once told him that she and Frank Sinatra were big fans of the series.

According to Sir Roger Moore in his autobiography, producer Robert S. Baker never gave Leslie Charteris script approval. He only had the right to comment on them. The short stories on which many of the episodes were based had a first and third act, but the show's writers had to go back and add a second act, in order to fill the entire hour.

The earlier episodes tended to include elements of mystery and intrigue.

Sir Roger Moore gained a reputation for being a bit of a prankster on the set.

The series was one of two similar hopefuls the production company had lined up for the 1962-63 season. The other was Man of the World (1962), which had cost more money, but had a different style that did not catch on, and was cancelled.

Out of all of the actors who played Inspector Claude Eustace Teal during the series, Ivor Dean featured most frequently in the role.

During the black-and-white part of the series, Sir Roger Moore played Simon Templar with an American accent (as the character from the stories hailed from the United States). By the time the color part of the series went into production, the accent became more English.

Even though the two-part story Vendetta for the Saint (1969) was set in Italy, the location shooting took place in Malta.

Most of the location footage from the series was either archive footage or second unit photography. The actors and actresses were rarely involved.

Simon Templar was Jewish.

At one point, this show shared some of the soundstages with that of The Baron (1966).