Roger Moore was doubled for almost all long shots, even when just walking down the street. This was to save production time and money, meaning the star was free for closer work which couldn't be shot around him, and was common practice on all ITC series.
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.
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.
Whilst putting the series together, it was decided to make the Simon Templar character more likeable than in the stories and far less violent.
In order to give the Simon Templar character a more 1940s look, Sir Roger Moore wore a hairpiece.