Later in the season, Karl offers to marry Susan when she needs a life-saving surgery so that she can use his health insurance to pay for it, but they plan to divorce soon after Susan's surgery. Ron Mc Cready's relationship and he knows that Susan had not yet mentioned her and Mike's past, so Karl breaks open a pipe under the sink and Ron gets Mike and he learns that Susan had lied to him and Karl watched happily as Ron dumped her.
Later in the series, Karl asks Edie to marry him; however, when Edie learns of their sham marriage, she demands that Karl propose to her and throw her a lavish wedding.
In his will, Karl leaves Susan his partial ownership of a local strip club.
Richard Burgi makes one last, uncredited appearance as Karl in the series finale, "Finishing the Hat", as one of the ghosts that watch Susan and her family leave Wisteria Lane.
In the five year leap on season five it's presumed Karl and Marissa had their child.
Karl reappears in the second episode of the fifth season, where he was asked by Julie to pick up and help her with her insurance.
Bree overhears from the kitchen and lets out a sigh of relief.Bree notices the activity going on inside Santa's Workshop, and goes in to stop Orson and Karl from fighting.When the plane slides into the party, it smashes into Santa's Workshop and after the crash a bloody hand is hanging out from one of the Workshop's windows.Burgi returned for the series finale, appearing as his character's ghost among other deceased characters.He even goes so far as to lie to Susan and say that he was breaking it off with Edie, which led to him and Susan having sex.