The series' second season introduces veteran actor[1][2] Danny DeVito portraying Dennis and Dee's father Frank, who moves in with temporary wheelchair user Charlie following a car accident, and blackmails his way into the group.

The gang ups their efforts on the scheming front: the gang tries to fight back against a property anomaly that leaves their bar in the path of an Israeli immigrant's new place, Dennis and Dee quit their jobs and hatch a plot to get on welfare so they can live out their dream careers, and Frank—along with Charlie and Mac—exploit the religious when they discover a water stain in the back room that resembles The Virgin Mary.

Charlie and Dee fight against cigarette smoking, while Frank, Mac, and Dennis fight back against their freedoms being encroached by making their bar an "anything goes" establishment that first attracts drunk college girls willing to flash their breasts for beads, but things do not go according to plan when heroin addicts, Vietnamese gamblers, and the incestuous McPoyle siblings get in on the action.

Before production of the second season began, series creator Rob McElhenney found out that Danny DeVito was a fan of the show and a friend of FX president, John Landgraf.

The website's critical consensus reads, "The Gang becomes complete with the addition of Danny DeVito, whose wily performance gives Always Sunny a new shine.