John Barrowman was up for the role of Will, but didn't get it because he was "too straight", and the role went to Eric McCormack. Barrowman is gay in real-life, while McCormack is straight.

Megan Mullally originally used her normal voice in the first episode. She began using her trademark high-pitched nasal voice in the second episode.

Rosario was a one-joke character in the first season, when Jack married her so she could stay in the country. The character became so popular, that she was made a semi-regular.

Megan Mullally's real-life husband Nick Offerman played Nick the Plumber in season four, episode nine, "Moveable Feast Part 1", and returned in 2018 as a celebrity chef who sleeps with both Will and Grace.

Among the four main cast members, Sean Hayes received most award recognition for his work, with a total of forty-four nominations, Megan Mullaly achieved forty nominations, Debra Messing got thirty-six, and Eric McCormack received twenty-eight, during the original eight season run.

As revealed in an interview, when Megan Mullally learned she won the role, she was leaving NBC studios and made an illegal u-turn. She was pulled over, but said it didn't matter, because she's on a new show.

Grace's middle name is Elizabeth. It is explained that this is because her mother was a big fan of Elizabeth Taylor. In real-life, Debbie Reynolds, who plays Grace's mother, had her husband leave her for Elizabeth Taylor.

Megan Mullally was offered Karen and the role of Carrie in The King of Queens (1998). She almost went with the latter role.

Former Vice President Joe Biden honored the show to be a trailblazer for acceptance of the LGBT community, as well as paving way for endorsement of same-sex marriage. He said, "I think 'Will & Grace' probably did more to educate the American public than almost anything anybody has ever done so far. This is evolving."

One of only three television series to win Emmys for all of their principal cast members. The others are All in the Family (1971) and The Golden Girls (1985), with all three shows featuring a regular cast of four.

In a surprise announcement from NBC, this show returned to television after an eleven-year hiatus. What makes it all amazing is the show returned with the original cast, original director, original producers, and airing on the original network as well. The original announcement indicated there would be ten episodes, but NBC soon announced there would more coming.

Jack's website really does exist. It now redirects you to NBC's Will & Grace website, but at the time it was created, it was an actual website created by "Jack". It included pictures, and a letter Rosario wrote to the I.N.S.

James Burrows directed every episode of the first eight seasons, an impressive total of one hundred eighty-eight episodes.

Jack's Cher doll is a sixty thousand dollar prototype of a doll that Mattel sold for a short time in 2001. Co-Producer and Creator Max Mutchnick currently owns the doll that was featured in the show.

Early promotional spots for the show were ambiguous about Will's homosexuality, since NBC didn't know how well the gay leading character would play.

Originally, Max Mutchnick and David Kohan pitched a straightforward couples comedy in which a gay man and his straight female roommate were supporting characters. NBC liked the supporting characters better.

Megan Mullally once developed a Broadway musical which revolved around her character on this show, titled "Karen: The Musical". The musical would be centered on Karen Walker's rivalry with Beverly Leslie, with Leslie Jordan set to appear as well. Mullally secured the rights to the character from NBC, had backing from Fox Theatricals, and had lined up a director, and a composer for the show, before certain stakeholders in the Karen Walker character withdrew the rights for its use in the production.

Will originally had a partner in the original pilot, Higgins, but his scenes were deleted in the final draft of the script.

When Cher and Madonna made their respective appearance on the show, filming of their entrances had to be taken several times, as uproarious applause from the live studio audience ruined the audio tracks.

Karen's maiden name is Delaney. Her full name is Karen Delaney St. Croix Popeil Walker.

Because of the show's numerous pop culture references, many of the celebrity guests had already been mentioned on the show before their eventual guest appearances (for example, Alec Baldwin, Matt Damon, Madonna, Britney Spears, et cetera).

Due to Debra Messing's pregnancy during the sixth season, Grace did not appear in five episodes: episode six, "Heart Like a Wheelchair", episode twenty-one, "I Never Cheered for My Father", episode twenty-two, "Speechless", episode twenty-three, "I Do", and episode twenty-four, "Oh, No, You Di-in't".

Alexis Arquette lost the part of Jack to Sean Hayes at the final auditions.

Eric McCormack and Debra Messing worked on an episode of The Mysteries of Laura (2014). The guest part was written for McCormack, who described working with Messing again to be "like riding a very old, creaky bike."

The Smithsonian's National Museum of American History exhibits memorabilia from the show, as a part of documenting the history of LGBT Americans. Featured are original scripts, casting ideas, political memorabilia surrounding the show, and the season eight finale, plus network donated props, such as a sign from "Grace Adler Interior Design", Will Truman's framed college diploma, the portrait of a young man that hung in Will and Grace's New York City apartment, as well as Karen Walker's pill bottle and flask.

Nicollette Sheridan lost the part of Grace Adler to Debra Messing at the final auditions.

The renewal in 2017 was originally only a limited return, featuring ten new episodes. This was expanded to thirteen episodes, but the day after the first table read, NBC announced the season had been expanded to sixteen episodes, and an additional season had been ordered as well.

Will's brother, Sam, was portrayed by two different actors, each appearing in two episodes: John Slattery in 1999, and Steven Weber in 2005 and 2006.

Karen Walker's husband, Stan, is never entirely seen. However, in Will & Grace: New Will City (2000), viewers do get to see parts of Stan Walker. He reaches out and grabs Karen's breast while she is talking to Will and throughout the scene, viewers can see Stan's legs, though most of him is blocked by a plant.

In the episode where Grace is going to meet an old high school crush, he says he's part of a group of artists showing their art at the Zelman Gallery. Debra Messing's (Grace's) real-life husband is Daniel Zelman.

The pose Jack uses for his "Just Jack" show slogan, is based on Judy Garland from A Star Is Born (1954).

The first episode of the eighth season was a live-aired episode.

Patrick Dempsey starred in three episodes of the show. He later presented Megan Mullally her second Emmy Award, when she won for Outstanding Supporting Actress in a Comedy Series at The 58th Annual Primetime Emmy Awards (2006).

The part of Beverly Leslie, that was ultimately played by Leslie Jordan, was originally to be played by Joan Collins. The first episode with the character called for a fight between Karen Walker and Beverly Leslie wherein each character pulls off each other's wigs. At the last minute, Joan Collins refused to have her wig pulled off and Leslie Jordan was cast.

Megan Mullally joked that the renewal in 2017 was the last order commissioned by former President Barack Obama. Mullally, a huge Obama supporter, once had to perform Karen Walker next to Donald J. Trump, during The 57th Annual Primetime Emmy Awards (2005). She has referred to this as her "suicide note".

Veronica Cartwright and Suzanne Pleshette respectively played the mothers of Jack and Karen. Cartwright and Pleshette appeared in The Birds (1963).

Director Sydney Pollack guest-starred in four episodes as Will's father, who cheats on Will's mother (played by Blythe Danner) with a woman named Tina (played by Lesley Ann Warren).

Will's apartment building is at 155 Riverside Drive, Upper West Side Manhattan.

The Grace Adler Designs office is located in the Puck Building at 295 Lafayette Street, south of Houston Street.

Jack's full name is John Phillip McFarland.

All of the four principal cast won an Emmy in their respective categories over the course of the shows run, with Megan Mullally taking home two for her portrayal of Karen Walker. However, only two years saw all of the cast nominated at the same time, 2000 and 2001. The show managed at least one win in any category, with the exception of two years, The 51st Annual Primetime Emmy Awards (1999), of which it was only nominated in one category, the direction of the pilot, and The 56th Annual Primetime Emmy Awards (2004), in which it was conversely nominated for nine. In only one of it's six nominations did it ever take home the Emmy for Outstanding Comedy Series.

During the episode in which Will and Grace compete for the Tenants Association Presidency, one tenant complains that her missing umbrella closely resembles the one belonging to "Tim Kaiser in apartment 12-B". Tim Kaiser was a Producer of the episode.

Yasmine Bleeth auditioned for the role of Grace.

Several people appeared as gay characters (or "suspect") on this show before officially coming out in real-life, such as Richard Chamberlain, Neil Patrick Harris, and Sean Hayes (Jack).

If Grace had given birth to a daughter, she wanted to name her "Lilly".

In one episode, Karen mistakes Grace's last name for "Alden". One of the producers on the show is Bruce Alden.

In season nine, episode six, "Rosario's Quinceañera", Grace Adler (Debra Messing) is crying about her mother Bobbie Adler's (Debbie Reynolds') death. Debbie passed away December 28, 2016, the day after her daughter, Carrie Fisher, died.

Jarrod Emick read for the part of Will.

Universal Television is distributing the new seasons (from season nine on) instead of Warner Brothers Television.

At the beginning of the first episode where Debbie Reynolds guest stars (S1, E13), Jack, Will, and Grace talk about Star Wars which stars Carrie Fisher, Debbie Reynolds' daughter.

The 2017 revival disregarded the events of the final episode of the eighth season, in which Will and Grace had a falling out and only reunited a few decades later when their children attend the same university. This also meant disregarding the cliffhanger of whether Grace married Leo and had his child, or raised one with Will.

From season nine on, Rosario Salazar was killed off since the actress who portrayed her (Shelley Morrison) declined to reprise her role after retiring from acting.