from 1961 to 1969
David KeelMartin KingVenus SmithCathy GaleEmma PeelTara KingPurdey and Mike Gambit
From 1961 to 1969 John Steed had six different partners, two male and four female partners. Four of them worked with him for a longer period: Dr. Keel, Dr. Catherine Gale, Emma Peel and Tara King.

Only one of them was a professional agent like Steed. It was his last partner Tara King, all the three long time partners were "talented" amateurs.

During The New Avengers John Steed had two younger partners: Purdey and Mike Gambit.
John Steed's Partners
[Steed's Irregulars]