|Portrayed by||Jamie Thomas King|
|First appearance||Guy Walks Into an Advertising Agency|
|Final appearance||Guy Walks Into an Advertising Agency|
|Employer||Puttnam, Powell, and Lowe|
Guy MacKendrick was an accounts executive of London-based advertising firm Puttnam, Powell, and Lowe.
He was brought in by PP&L to take over the Sterling Cooper Advertising Agency. Saint John Powell and Harold Ford expressed much enthusiasm for him. During the drunken office party to welcome the company's reorganization, Lois Sadler accidentally runs over MacKendrick's foot with a John Deere riding lawnmower. Joan Holloway saves his life by quickly placing a tourniquet on his leg, however he ultimately loses his shredded foot.
Because of this disfigurement Powell and Ford decide that MacKendrick has no future with the firm and is fired. ("Guy Walks Into an Advertising Agency")