Argyle first appeared in The Pretender as the somewhat wacky and almost unlovable character who rescues then effectively kidnaps an injured Jarod and holds him hostage in the Season 2 episode Amnesia. He discovers many things about Jarod while going through Jarod's belongings and, ironically Jarod has had amnesia due to his head injury and cannot remember who he really is, the confusion being compounded by his possession of many different identification cards. When Argyle realises Jarod is of value to the Centre, he tries to sell Jarod back to them but does not quite succeed.
Argyle also appears in the Season 3 episode Unsinkable and the Season 4 episode Cold Dick and we see some of his less-annoying qualities, although he is still a character who appears to deserve his troubling plight. Jarod feels sorry for Argyle and so the viewers empathize with Jarod's tolerance of Argyle and see him in a more favorable light than in the episode Amnesia.
Argyle is not your typical villain even in his first appearance and it is possible Jarod saw the potential for goodness in him, because Argyle took such good care of his dog, which he had rescued from the Pound and named "Dog" and, he also tried to do something nice for his father even if his means were somewhat questionable.
The role of Argyle is played by Leland Orser.