Jefferson Milhouse D'Arcy (played by Ted McGinley) is the alias of Marcy's second husband (younger than Marcy; one episode mentioned that he celebrated his 40th birthday), a "pretty boy" who marries her for her money. Self-centered and lazy, he is a male equivalent of Peggy. Marcy met Jefferson (a bartender) at his workplace after a bankers' convention when she got drunk, and found herself married to him the next morning; she was horrified to find out that her name was now Marcy D'Arcy (Episode 92, "Married... with Who?").
Not much has been said about his childhood. Jefferson mentioned that his father once told him as a child "Shake it son and the women will pay"  which was inspirational to him. Marcy mentioned that both of his parents were sex workers that died tragic deaths. His dad was a gigolo who worked into his 70s suffering from back issues and died in a tanning booth accident. His mother was an exotic dancer at an all nude stripclub who was killed after her pet snake swallowed her during her break at work. Marcy also mentioned that there is 8mm footage of Jefferson's dad performing a fan dance for J. Edgar Hoover, the first Director of the Federal Bureau of Investigation (FBI) of the United States. 
He attended college and belonged to a fraternity that had lots of women, booze and fun. One time, he and his frat brothers got drunk on champale and grenadine and stuffed a Mr. Potato Head toy with cherry bombs, causing it to explode. He also appears to be still active with his fraternity, noting that he planned to attend a reunion with them. He also joined his frat brothers to help judge the Miss Spring Break contest in Fort Lauderdale, Florida
He mentioned that he took birdwatching while in college to meet women and was able to recognize a specific birdcall coming from the Bundy's backyard. He also drove a moped during his college years.
In "The D'Arcy Files", he told Marcy that "Jefferson D'Arcy" isn't his real name and that he was a CIA agent for several years, doing covert operations that sent dangerous criminals to prison. Things were going smoothly until a man named Walter Traugott escaped and caused Jefferson to fear that his cover will be exposed to the public. Traugott stops by Gary's Shoes & Accessories for Today's Woman and reveals to Al that Jefferson is the actual criminal (and Traugott implying that he is the actual CIA agent out to arrest him), stating that Jefferson is a double agent who sold government secrets to foreign leaders. As proof, he shows Al pictures of Jefferson talking with political figures Fidel Castro and Yasser Arafat.
In "Requiem for a Chevyweight (Part 2)", Jefferson is in fact on friendly terms with Fidel Castro. He told Castro that he lost his job at the CIA because he was unwilling to kill him in an assassination attempt.
Although he has been out of the CIA for some time, he is shown to still have some connections within the agency to help him out. Those connected allowed him to eliminate Traugott, covertly fly him into Cuba or access a pair of federal agents known "Geronimo" and "Chopper" who help him and "NO MA'AM" get into Congress.
At some point, he became a white collar criminal, selling plots of land around a toxic waste pond called Lake Chicamocomico and running off with the money before anyone realized what it truly was. He was caught and served time in prison, saying that he wasn't proud of it, but more so because he got caught in the first place.  Despite this, he continued running money schemes such as selling "lucky numbers" to people as "Madame Zelda". 
More about Jefferson
He is easily the most financially-scheming character of the show—even more than the Bundys. Often, when Al stumbles into a unique lucrative opportunity, Jefferson typically persuades Al to take advantage of it. When Al was robbed in his shoe store, Jefferson convinced him to sue the mall while feigning psychological trauma. When Al discovered hidden shoes that he stocked away in the 1970s, Jefferson convinced him to use the shoes as a new gimmick for the store by taking advantage of the old shoes' popularity. When discovering Al's boss, Gary, was using illegal sweatshops to manufacture the shoes, Jefferson assists Al in a search for incriminating evidence. When Bud was involved in a romantic relationship with the (surprising to the characters) female Gary (played by Janet Carroll), Jefferson convinced Al to permit the relationship, so Al can milk Gary out of her money through his son.
After discovering that they were in possession of private pictures of Shannon Tweed in sexually provocative manners, Jefferson convinced Al to sell it to the media. During a rare time in which Al is struck with good luck, Jefferson persuades him into a high stakes poker game with a group of ex-criminals. Jefferson also convinced Al to go home to have sex with his wife, so Al could win a radio contest.
During the course of the series, it is revealed that Jefferson spent time in prison for selling contaminated land as a vacation spot to several people, including Al. He also used to be in the CIA and according to the episode The D'Arcy Files, was known by another name than Jefferson D'Arcy, which he explained to Marcy was an alias. During that episode, he shows that he is more intelligent than he gives off. Occasionally, people claim to have seen him on The Love Boat and Happy Days (a reference to McGinley having starred in both shows towards their end of their original broadcast runs), but Jefferson always denies this.
Marcy constantly bosses Jefferson around to keep him in check. However, behind her back, Jefferson often insults Marcy, ignores her orders (and has implied numerous times that he cheats on her). When Marcy's favorite squirrel Zippy dies, Jefferson tells her that he will give it a proper burial, only to put it out of his sight when Marcy turns around. His full name is given in "Sleepless in Chicago".
Marcy constantly hounds Jefferson to get a job. However, on the rare occasions when he actually gets one (working at the shoe store, being cast as an actor in a commercial, working as a bartender, working as an aerobics instructor, working at an auto repair shop in some menial position, etc.), he usually ends up working with beautiful women, which prompts a jealous Marcy to make him quit and return to his de facto job as her gigolo. This tendency runs in the D'Arcy family, as Jefferson's father also worked as a gigolo, and his mother worked as an exotic dancer before she was eaten by her snake at an airport.
Jefferson is Al's neighbor and closest friend, often addressing Al as "Buddy", despite an age gap of several years betweem them. Their friendship often angers Marcy whenever he is bonding with him and the other members of NO MA'AM; unlike Steve who was more of a foil, or straight man, to Al. Jefferson tends to be very encouraging and attuned to Al's behavior. Also, in contrast to Steve, Al and Jefferson have similar tastes and will bond over things such as The Three Stooges or ogling women at The Jiggly Room.
Jefferson is a member of "NO MA'AM" along with Al, and serves as the group's note recorder. He is usually wearing the trademark t-shirt, but he always keeps a clean "YES MA'AM" t-shirt on underneath, which he quickly reveals if Marcy is about to bust one of "NO MA'AM's activities. He seems very afraid of provoking his wife's anger, and his fear is justified—in one episode, after he angered Marcy, she kicked him in the behind so hard he had to go to the hospital to get her boot removed from his rear end. In another instance, when Marcy returns from a camping trip with Al and Peg Marcy, angered that Jefferson charged all types of purchases on one of Marcy's credit cards, Marcy responds by pulling his pants up by his belt so high, it gives him a painful "wedgie"!
- Ted McGinley had appeared previously as Peggy's husband, Norman Jablonsky, in "It's a Bundyful Life (Part 2)", where Al's guardian angel (played by the late Sam Kinison) shows Al what his family would have become if he was never born.
- In several episodes, such as "Kids! Wadaya Gonna Do?" and "Guess Who's Coming to Breakfast, Lunch and Dinner", Jefferson mentions that he plays racquetball.
- Marcy implies that Jefferson is not a natural blonde in "Frat Chance".
- He has a personal apartment that Marcy doesn't seem to know about as mentioned in "Guess Who's Coming to Breakfast, Lunch and Dinner".
- He has a personal maid named Maria that Marcy doesn't know about in "Al Goes Deep" .
- Although it is mentioned that Jefferson is younger than Marcy, in real life, Ted McGinley and Amanda Bearse are the same age.
- Like Al, he is a fan of The Three Stooges and has stated that his favorite member was Moe Howard in "Love Conquers Al".
- I Want My Psycho Dad: Second Blood (Part 2)
- I Who Have Nothing
- Dud Bowl II
- Kiss of the Coffee Woman
- I Can't Believe It's Butter
- Banking on Marcy
- Spring Break (Part 2)
- Birthday Boy Toy
- Al on the Rocks
- Get the Dodge Outta Hell
- Radio Free Trumaine
- The D'Arcy Files
- Requiem for a Chevyweight (Part 2)
- The Desperate Half-Hour (Part 1)
- Cheese, Cues and Blood
- The Proposition
- 'Tis Time to Smell the Roses
- Damn Bundys
- The Legend of Ironhead Haynes
- Frat Chance
- Blonde and Blonder
- Kelly Takes a Shot
- Movie Show
- Married... with Who?
- Psychic Avengers