Virtually identical in format and style to the later Secret Agent (1964) with two major differences: John Drake is an American in this series, and episodes include narration.

Based on his success as John Drake, Patrick McGoohan became one of the first actors considered for the role of James Bond in Dr. No (1962). Between this series and the later Secret Agent (1964), three of the "regular" actors and actress in the Bond movies, Bernard Lee, Lois Maxwell, and Desmond Llewelyn, guest starred with McGoohan, as would many future Bond co-stars such as Honor Blackman and Zena Marshall to name just two.

In this early series, the character of John Drake is clearly defined as being an American. When the character returned for the second Secret Agent (1964) series, the character had become either British or Irish (exactly which was never settled upon definitively).

In the series' opening title sequence, the shot of Washington, D.C. is a composite of the Washington Capitol in the background and the Castrol Building, complete with London Bus stop, in the Marylebone Road, London as the foreground. This building is now the residential Marathon House having been converted from offices to flats in 1998.

John Drake says the phrase "I'm obliged" in virtually every episode. The catchphrase did not return in the 1964 series.

The first episode was filmed in the northern Wales village of Portmeirion. Patrick McGoohan returned there to film "The Prisoner (1967)."

Although hugely successful in Europe, this show failed to find an audience in American syndication and was cancelled after one season. By the time production resumed in 1964, the James Bond fad had hit and Americans were more receptive to the idea of a spy television series.

Contrary to publicity surrounding this show's DVD release in 2003 that suggests this series was never shown in America, this show was indeed broadcast in the U.S. in 1961, and under its original title.

Tht show resumed production with sixty-minute episodes in 1964. It was renamed "Secret Agent" for American distribution.

When Patrick McGoohan was shown a couple of early scripts, he demanded a few changes be made. The actor refused to allow Drake to become intimate with any woman, to use a gun as a means of killing, and to avoid making Drake a "one-dimensional muscle head".

With a running time of thirty minutes per episode, the stories never allowed much time for any character development or subplots. The emphasis would always be on action and dramatic incident.

This show was the first major success for Producer Sir Lew Grade after some of his previous television efforts had failed.

Patrick McGoohan was the only regular cast member throughout the series. However, Richard Wattis made a few appearances as Drake's boss.

Unlike the later series, the thirty-minute episodes didn't show John Drake relying upon any gadgets to get him out of trouble.

This show heralded the public's interest for spy fiction in the entertainment industry. This was a year before The Avengers (1961), and two years before James Bond (a role which was offered to Patrick McGoohan).