Clancy Bouvier was the husband of Jacqueline Bouvier, the father of Patty, Selma, and Marge Bouvier and the maternal grandfather of Ling Bouvier and Maggie, Lisa, Hugo (non-canon), and Bart. He is of French origin.
Like Patty and Selma, he was a chain-smoker. When he was first trying to catch his future wife's eye, he sent her a box of candy with his photo in it. After that, she never forgot him. Marge suggested try the same thing when Homer was upset because Mr. Burns did not remember his name.
He was one of the earliest male flight attendants, although he was ashamed of it. This was discovered when Marge boarded his plane to see her "pilot" father, but when she sees him performing stewardess duties, he yells at her not to look at him. This, along with several other plane-related mishaps, may have resulted in Marge's fear of flying. At some point, he also served in the United States Navy where he picked up a swearing problem, which nearly cost him his job as a baby photographer.
In the season 3 episode "Bart the Lover", Ned Flanders and Marge think Homer swears too much. Marge tells Homer the above story of her father almost losing his job due to his swearing problem. To solve this problem, Jacqueline put a swear jar in the kitchen. then every time he said a bad word he put in a quarter. It worked for Homer, and apparently it worked for Clancy, too.
Approval of Homer
Clancy first met Homer when he showed up at the Bouvier home claiming to be Marge's prom date. He was kind and complimentary to Homer, saying, "From what she's told me, I'm sure you're a solid citizen." Whether Marge had "sugar-coated" her description of Homer, or she had in fact been describing Artie, is unclear.
It is revealed later that his behavior towards Homer was still prevalent, even after Artie's arrival: When Marge returned home after the prom, she overheard her father stating that "when that Simpson boy showed up, it took years off my [his] life", to which her mother replied, "Will you stop? She went with the good one." (She was referring to Artie.)
Ever since his kids were little, Clancy went to Springfield Town Hall to sing the City Anthem, and continued to do so as he aged. He was still alive when his grandchildren Bart and Lisa were toddlers.
It was later revealed by Jacqueline that he died of lung cancer. 
We know that Clancy is deceased from the only episode where his death is mentioned (Jazzy and the Pussycats), where Homer says he had bought Marge a "white-noise machine" to help her deal with her father's death. The cause or time of his death is undetermined. In an issue of the comic Simpsons Illustrated, Lisa reveals that Clancy died in an accident in 1985. What is known is that his death occurred some time after Lisa and Bart reached a toddler age, since he still appeared alongside toddler Bart and Lisa in "Walking Big & Tall". Clancy is also known to be dead because he never appears with Jacqueline, who is portrayed as a single woman.
In one Treehouse of Horror episode, he was eaten by King Homer at his and Marge's wedding.
- Episode – "The Way We Was" (flashback)
- Episode – "The War of the Simpsons" (mentioned)
- Episode – "Bart the Lover" (mentioned)
- THOH – "Treehouse of Horror III"
- Episode – "Fear of Flying" (flashback)
- Episode – "Who Shot Mr. Burns? (Part One)" (mentioned)
- Episode – "Jazzy and the Pussycats" (mentioned)
- Episode – "The Color Yellow" (mentioned)
- Episode – "Walking Big & Tall" (flashback)
- Episode – "Puffless" (Seen on slideshow and mentioned)
- THOH – "Treehouse of Horror XXVI" (As a ghost in samurai clothes in "Homerzilla")
- Book – The Simpsons Uncensored Family Album
- Book – The Marge Book