Jack was born in February 16, 1969 and was raised as an only child by Judith and Daniel McFarland. Jack mentions that he was born via Caesarean section thereby considers himself "platinum gay" or a gay man who has never been in contact with a vagina. Jack grew up in 125th Street in New York.
Jack recalls that his father was discouraging and cruel to him growing up gay. Daniel once gave Jack a ball for his birthday, which he put under his shirt and told everyone he was pregnant with George Michael's baby. According to Jack, Daniel passed out when he came out to him, at which point he had to perform CPR. Once as a kid, Jack set up a manicure stand at the end of the street and waited for his father to stop by but he never did. He eventually finds out that Daniel is not his biological father, but rather a man named Joe Black, whom his mother had anonymous sex with at a pool party in 1968. He writes a letter to him but finds out later that he is already dead.
As a kid, he was babysat by Sissy. Jack also mentions being an altar boy at Saint Margaret. Jack's childhood is mostly marred by the bullying he suffered for being different, including being called "Jack McFairyland" in elementary and being beat up by the football team. Jack eventually grows up comfortable in his own sexuality and a penchant for performing.
When Jack was 17, he donated sperm to the New York Family Clinic to earn money for a leather coat. He finds out 13 years later that a nurse working at the clinic took his sperm, hence becoming the biological father of Elliot.
While in high school, Jack befriended Will Truman, a college freshman who was still in the closet. Being proud of his sexuality, Jack encouraged Will to come out and embrace who he is, after which they became really close. Jack confessed his attraction to Will a year later, which he politely turned down. Jack later admits that he bribed the first guy Will went out with to boost his confidence.
Although openly gay to his friends, Jack never came out to his mother, fearing she will not be able to handle having a gay son and "fall apart" if she finds out, even telling her that he and Grace were once a couple. According to Will, Jack told an elaborate story about him coming out to his mother to avoid peewee football.
After Will asks him the same question Jack asked him before he himself came out ("aren't you tired yet?"), he eventually comes out to his mother on Thanksgiving on 1999.
Jack has become notorious for switching jobs frequently (every episode in the earlier seasons), while supporting his acting career. He has become a cabaret singer, cage dancer, cater-waiter, backup dancer to Jennifer Lopez and then to Janet Jackson, assistant to Grace, a candidate for the Manhattan Gay Men's Chorus, a sales clerk at Banana Republic and Barney's New York, a student nurse, a surfer, a playwright, a novelist, a commercial and theater actor, an acting teacher, a magician, a junior executive and a talk show host at OutTV, before ultimately being cast as the lead in the crime drama The Badge as Chuck Rafferty, a straight hard-boiled detective. It was also mentioned that Jack was fired from a restaurant for stealing wine, and from his job at a library, a Swiss Colony, and by his grandmother. Will mentions that Jack once worked at a Starbucks where he harassed one of his co-workers.
As an actor he is mentored by Zandra before he himself becomes an acting teacher, teaching The McFarland Method. Starting season five, he also runs Jacques, a one-table café in the hallway outside his front door.
Jack has stated that he loves acting because of the attention and the applause. Will, Karen and Judith support Jack while he jumps from career to career and until the first season, he doesn't pay taxes.
Portrayed as a confident gay man, Jack has always had a passion for acting and the theater, although his friends frequently express doubt in his abilities. He later graduates from nursing school with flying colors but still realizes that acting is what he wants to do in life.
Jack is also shown to be somewhat slow, that Will claims he could not count to ten, and that he still labels his shoes "L" and "R". Despite this, Jack is also shown to be a creative writer as he claims he completed three short novels when he was 10, and he wrote "To Weep And To Willow: A Harlequeen Romance" which Karen loved.
Strangely, Jack believes in gay rights but seemingly disdains heterosexual as well as lesbian relationships, saying that "if God had intended man and woman to be together, he would've given them both penises". According to Will he has the best gaydar in the tristate area. On several episodes, Jack has shown a habit of expressing shock using famous celebrities with long names, such as "Sarah Jessica Parker! Hide me!", "Holy Anne Heche Laffoon he's straight!", "Britney Spears Federline, a gym!", and "Billie Jean King! There are lezzies in this!".
Jack is also implied to be an animal lover, being the owner of Guapo even before the beginning of the series, Klaus Von Puppy since the first season, and in the fourth season, he and Karen bought Lamar, a horse who turned out to be gay. In the eighth season, Jack donated enough money to the zoo so two gay penguins will not be separated.
Jack unashamedly adores all gay icons particularly Cher, of whom he has a rare doll. He meets her once at a restaurant, although he mistakes her for a drag queen and declares that he can "do a better Cher than [her]". Cher slaps him and leaves at which point Jack realizes who she is and faints. Cher reappears in Jack's dream as his personification of god.
Jack is also a big fan of pop culture and television, which helped him in his job as an executive at Out TV. He is a fan of Buffy the Vampire Slayer, particularly lesbian character Willow Rosenberg. He also collects clippings of celebrities' hair, including a complete collection from the four main actresses on The Golden Girls, as well as Broadway icons Bernadette Peters, Betty Buckley, Idina Menzel, and Patti LuPone. Jack is also an active stalker of actors Kevin Bacon and Mark Wahlberg. He, along with Grace, also loves figure skating and once even went out with Rudy Galindo.
Will became Jack's best friend shortly after he came out. Will mentions Jack helping him through this period he considers the most difficult time in his life which he repays by supporting Jack for most of their lives. Jack has confessed his attraction to Will, and after thinking they have slept each other during a black out, Will also admits being attracted to Jack but they decide to maintain a platonic relationship. A psychic once told Will that the man he is going to spend the rest of his life with is a man named "Jack".
As joke, Will often pokes fun at Jack's promiscuity, flamboyant personality and seemingly hopeless career and Jack often points out that albeit untrue Will is overweight and that he is losing his hair. Jack has accidentally stated that he has an "I love Will" tattoo on his butt.
Grace and Jack became friends mainly because of Will. They initially expressed that they didn't have anything in common until they discovered they both love figure skating, Antiques Road Show, and gay porn and they begin to bond.
Along with Karen, Jack frequently makes fun of Grace's physical attributes as well as her wardrobe. By the start of season three, Grace and Jack have become really close which even drove Will jealous.
Jack meets Karen in the second episode of the first season and they immediately become best friends for the entirety of the series, their friendship even outlasting that of Will and Grace's. They are known for their cutesy repartee; Jack calling Karen "Kare" and her calling him "Poodle" and the exchange "Who's your daddy?" "You are." Much like Will, Karen supports Jack financially, and frequently takes him on shopping sprees, which for him, is the main driving force of their friendship due to his admittedly shallow nature.Eric McCormack has referred to Jack and Karen as the "fun house mirror reflection of Will and Grace".
They also have a physical, borderline "sexual" relationship in which they consistently grope and make lewd remarks about each other. Although they have a lighthearted, comedic relationship, their friendship faces several obstacles, such as when Jack makes ridiculous demands from Karen in exchange for marrying her maid Rosario; when Karen finds out that he has also become friends with her rival Lorraine Finster; and when he tries to replace Karen after her engagement to Lyle. Their relationship also go through somewhat serious turns such as when Jack finds out Karen might be pregnant, and subsequently finds out about her "forbidden room".
Rosario was married to Jack briefly as a favor for Karen who was desperate for Rosario to get a green card. They slept on the same bed at the maid's quarters at Karen's mansion.
Other romantic relationships
- Jack accidentally implied that he has a tattoo saying "I Love Will" he got because he was drunk.
- Will mentions that Jack gets dates using the cyber name "Butt Masterson".
- Jack attended acrylic nail school and jeweled acrylic nail school each for less than a week.
- Sean Hayes' piano skills are often utilized in Jack's performances in Just Jack, Jack 2000, Jack 2001 and others. Hayes is a classically trained pianist.
- For his performance as Jack, Sean Hayes has been nominated for the Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series consecutively from 2000 to 2006, winning the first time.
- He appears to be a big fan of the show "Riverdale", as he nearly had a nervous breakdown in "Friends and Lover", when Will jokingly told Jack that the show had been cancelled in an attempt to get the Trucks for Tykes song out of Jack's head.
- Jack is allergic to bees.
- Sean Hayes is gay in real life.
I find that the one thing that really makes people smile is my music... or my oddly long tongue. Your choice. — Bed, Bath and Beyond
Does he have a gay brother? Or better yet, does he have a straight brother who drinks a lot? — Field of Queens
It's like all people see when they look at us are the supporting players on the Will & Grace show. — on him and Karen, The Finale
Heterosexual marriage is just wrong. If God had intended man and woman to be together, he would've given them both penises. — An Affair to Forget
I took an oath in front of God and my mother;
I'm here, I'm queer, get used to it! — The Buying Game
There are no straight men, only men who haven't met Jack. — Girls, Interrupted
There's no shame in getting old. There's only shame in getting ugly. — The Blonde Leading the Blind
- Emergency Contact
- Boo! Humbug
- Moveable Feast
- Alley Cats
- I Never Cheered for my Father
- Homo for the Holidays
- Sons and Lovers
- Women and Children First
- A.I.: Artificial Insemination
- I Never Promised You An Olive Garden
- Back Up, Dancer
- Lows in the Mid-Eighties
- Fagmalion Part Two: Attack of the Clones
- Between a Rock and Harlin's Place
- Grace 0, Jack 2000
- Last of the Really Odd Lovers
- To Serve and Disinfect
- I Do. Oh, No, You Di-in't
- William, Tell
- A Chorus Lie
- Love Plus One
- Loose Lips Sink Relationships
- Nice in White Satin
- The Big Vent
- An Old-Fashioned Piano Party
- Went to a Garden Potty
- A Buncha White Chicks Sittin' Around Talkin'
- The Needle and the Omelet's Done
- Hocus Focus
- One Gay at a Time
- Kiss and Tell
- Whatever Happened to Baby Gin?
- Yours, Mine or Ours
- Polk Defeats Truman
- Terms of Employment
- Where There's a Will, There's No Way
- Courting Disaster
- The Definition of Marriage
- Girl Trouble
- An Affair to Forget
- Yours, Mine or Ours
- The Newlydreads
- Whoa, Nelly
- Birds of a Feather Boa
- Gypsies, Tramps and Weed
- Bully Woolley
- Bacon and Eggs
- Saving Grace, Again (Part 1)
- Will on Ice
- The Old Man and the Sea
- Dames at Sea
- Alive and Schticking
- Tea and a Total Lack of Sympathy
- New Will City
- The Third Wheel Gets the Grace
- Say Goodnight Gracie
- Ben? Her?
- Fred Astaire and Ginger Chicken
- The Unsinkable Mommy Adler
- Forbidden Fruit
- Das Boob
- Sweet and Sour Charity
- Alive and Schticking
- My Fair Maid-y
- So Long, Division