Bill was apparently very fit in high school but since then has let himself go, putting on some weight.
Bill is a hedonistic and sleazy individual, with a highly addictive personality, frequently using alcohol and even drugs like "bath salts", and being very sexually active, having another mistress besides Dee, and lying to women that he had a vasectomy to avoid wearing condoms.
A deplorable, yet amusing individual, Bill has fallen into a downward spiral that he seems to have no problem with continuing, despite how badly it has ruined his life. He is unfaithful husband and abusive father, who treats his family horribly - he constantly cheats on his wife with other women (Dee included), telling his son he doesn't love him, calling his daughter fat and even putting weight loss pills in her food. His own family has come to utterly hate him due to his abusive treatment towards them, to the point that they actually hope he dies, showing just how badly the bridge between them has burnt. Bill shows no remorse and guilt for his past behaviour.
Bill has progressively shown suicidal tendencies as the series has gone on, even carrying a gun in his glove compartment in the case of wanting to end it.
His sister is Maureen Ponderosa. Dennis was briefly the brother-in-law of Bill.
Sweet Dee had a crush on Bill in high school. His sister Maureen dated Dee's twin brother Dennis in High School and recently married him and divorced him soon after.
He has a wife named Jane (shown in the credits for "Dennis Gets Divorced"). He also had a son and daughter which Dee unintentionally helps him kidnap.
His wife implied that Bill frequently pays women for sex. ("Dennis Gets Divorced")
When Mac, Charlie, and Frank question him to try to figure out if he could be the father of Dee's baby, he tells them that he has had a vasectomy... and then immediately admits that that's a lie he tells women to avoid having to wear a condom. He says he is still with his wife, and has undergone counseling for sex addiction. He's apparently replaced that with other addictions, however: he has brought a sizable bag of coke to the party, which he shares with other guests at the impromptu "party" that Mac, Charlie, and Frank are throwing to gather together the possible fathers of Dee's baby, and by the end of the party he is quite wired. He says that if the baby is his, he'll blow his brains out. ("Dee Gives Birth")
He attends Maureen's wedding, which Frank also attends as Bill's AA sponsor. However, Frank is hardly the model of a good AA sponsor, and he encourages Bill to do as many drugs as he wants at the wedding. Bill eventually spikes the punchbowl at the wedding (which is full of milk) with "bath salts", which leads to the zombie-like violent behavior that leads the wedding to descend into chaos. ("The Maureen Ponderosa Wedding Massacre")
Bill shows up at The Gang's Thanksgiving dinner, invited to shift the blame for Liam getting his eye eaten at his wedding from The Gang to Bill. Dennis tells Liam and Ryan that Bill spiked the milk with bath salts, but Bill then tells the McPoyles that Frank encouraged him to get "shithoused" at the wedding, so they shift the blame back to Frank. He also admits to breaking into Dee's apartment to sniff her panties.("The Gang Squashes Their Beefs")
Bill shows up at Paddy's, announcing that he has decided to drink himself to death. Dennis, Dee, and Frank decide to try to save his life (not so much out of concern for him as the fact that they don't want another death in the bar) by enlisting his family to help show him life is worth living, but he has completely alienated his family, who actually hope he dies. However, Dee and Dennis decide to take a life insurance policy out on him anyway, which upon learning of, Frank lets them know is "kinda dark," to which they tell him to "move past it." Eventually, the rest of the gang rescinds their judgment of the life insurance scheme, emphatically justifying to themselves that "a grown man should be able to end his life," and thus actively persuade Bill to commit suicide by confessing to the murder Luther McDonald has been accused of, but in the process of "confessing", Bill tells the police the actual killer, which frees Luther (but probably makes him a target for assassination from the real killer's gang.) ("Mac Kills His Dad")
Bill invites Frank out to party, but Frank can't go, because he is playing a role -- of some sort -- in The Gang's latest scheme. Later, Frank calls him to get a ride from the hospital, and Bill once again invites him to "rage" with him, saying that he has just divorced his wife and is trying to spend the money he has before his wife and kids can get it. Later, Bill sends Frank a "911" text, asking Frank to come get him. Frank picks Bill up at a roller rink, where Bill tells him he got handsy with "a sweet young thing" who he thought was 18, but, judging by the angry mob of dads looking to kick his ass, obviously was not. Bill attempts to commit suicide with a gun he keeps in his glove compartment, but Frank stops him, knocking the gun away. ("Being Frank")
Bill is interviewed for a documentary about Maureen's (alleged) murder. He says that as far as he's concerned, Maureen died three years ago, and Dennis -- who he believes murdered Maureen -- killed Bastet, which was the name Maureen went by after her human-to-feline transition. He doesn't seem particularly upset by this: "He did us all a favor. You ever seen a grown woman take a dump in a sandbox?" The interview looks like it's taking place in a really squalid apartment, and he sniffs loudly at a few points, implying his personal downward spiral continues. ("Making Dennis Reynolds a Murderer")
- Whenever Sweet Dee thinks about or sees Bill, she uncontrollably gags. ("Mac Fights Gay Marriage")
- Apparently, one of the conditions for Bill to be able to see his kids after his wife left him ("Dennis Gets Divorced") was for him to go through Alcoholic Anonymous therapy. But with a sponsor like Frank he'll never quite change his lifestyle. ("The Maureen Ponderosa Wedding Massacre")
- Bill and Frank became all buddy-buddy after the events of ("Dee Gives Birth") (thanks to the drugs Bill brings to the party).
- In season ten the Gang takes out an expensive life insurance policy on Bill that is presumably still active.
- Bill seems increasingly suicidal as the show goes along: in "Mac Kills His Dad", he announces his intention to drink himself to death, and in "Being Frank", he actually does attempt suicide with a gun he keeps in the glove compartment of his car, but Frank knocks the gun away.
- In his interview in the episode "Making Dennis Reynolds a Murderer", he sniffs loudly before he begins (suggesting heavy cocaine use), and he appears to be living in a squalid apartment.
- Ponderosa comes from the word "ponderous" meaning slow and heavy from great weight, which is a hint to Bill Ponderosa's size and weight
- Bill brought cocaine to Mac and Charlie's party, which he kindly shares. As Bill gets high and arrives to the hospital with the other potential dads, he says he will "blow his brains out" if he is the father of Dee's baby. ("Dee Gives Birth")
- Season Six: Mac Fights Gay Marriage, Dennis Gets Divorced, Dee Gives Birth
- Season Eight: The Maureen Ponderosa Wedding Massacre
- Season Nine: "The Gang Squashes Their Beefs"
- Season Ten: "Mac Kills His Dad"
- Season Eleven: "Being Frank", "McPoyle vs. Ponderosa: The Trial of the Century"
- Season Twelve: "Making Dennis Reynolds a Murderer"
- Season 13: Charlie's Home Alone, The Gang Wins the Big Game
- It’s Always Sunny: Gang Goes Mobile
- Has an ex-wife and kids, a son (who's also his drug dealer) and a daughter.
- Has had affairs with Sweet Dee and at least one other woman.
- Frank Reynolds is Bill's AA sponsor.
- Jane Ponderosa (ex-wife)
- Unnamed mistress
- handjob from -presumed- underage girl
- Japanese canakazzii sub pilots
- His own mother