Not much is known about Herzog aside from his 43 previous attempts at escaping Blood Island Penitentiary. Due to this, he has a particular antagonism with Ruth, Sam's grandmother and the former warden of the prison.
Herzog and his cronies arrange for yet another escape attempt during Ruth's visit to the prison over Christmas. With Sam and Max accompanying her, Ruth has to track down her old nemesis as he makes his attempt during a prison blackout. While the three cut him off at the showers, Herzog escapes into the Warden's office. Ruth catches and beats the criminal just as Santa Claus arrives. Herzog tries once more to escape and seemingly does-until Ruth receives a special gift of Herzog inside a Christmas present.
"The Final Episode"
Herzog appears as part of Mack Salmon's collective of villains in the final episode to exact revenge on Sam and Max. He doesn't get far though as he, along with The Mad Thespian, are booted from the plane carrying them due to Sam and Max wanting to thin them out. It can be assumed he was likely imprisoned once more.