Host, Judge and Producer of the Show.
- Boring, but Practical: Compared to other judges, she focuses on the wearability on the fashion design.
- Buxom Is Better: Expected as a former Victoria's Secret model. However, it's also usually her first criticism at garment construction.
- "One day you're IN, the next day you're OUT"
- "Auf Wiedersehen" to the eliminated designers.
- Cool Teacher: Subverted. She can be funny to watch, but some of the designers don't have that perception when her critiques are negative.
- Enforced Plug: In recent seasons, most of the challenges were based on Heidi's side-projects and brand projects, most notably New Balance.
The designers Mentor.
- A Father to His Men: If he gets too attached to the designers, he will genuinely be pissed or sad for their eliminations.
- Ascended Extra: Though he's never been what you might consider an extra, he was originally hired just as an offscreen consultant to the show until the producers noticed how well he got along with the designers and decided to have him appear on screen. And in season 12 he sits on the judging panel, giving the judges insight into the process behind a design, and has a "Tim Gunn Save" he can use to save an eliminated designer if he feels the judges have erred in their choice.
- Asexual: Though he defines his romantic orientation as "homoromantic", Tim Gunn is a self-identified Asexual. He hasn't been in a relationship since the early 1980s and says he has no interest in being in another one.
- Breakout Character: Had two Spin-Off shows — "Tim Gunn's Guide to Style" and "Under the Gunn", as well becoming The Face of the show when doing guest appearances in other media.
- Catch-Phrase: "Make it work".
- Celibate Hero: He once told that he hasn't been in a serious relationship since the last one ended up bad.
- City Mouse: During Andy's home-visit, Tim shrieks at the sight of catfish.
- Classical Tongue: Season 3 reunion rolled a footage of Tim's refined language in action, which required dictionary quotation at the designer's blank faces. Words included: "Mitigating", "Faux-bois", "Consternation", "Sturm and Drang", "Caucus" and many others.
- Sometimes goes into Sophisticated as Hell when interacting in the workroom with some of the designers, immediately laughing.
- Cool Old Guy: Many of the designers, despite his sometimes harsh criticism, consider him this.
- Cooldown Hug: He's in charge of giving this to the stressed designers.
- Dark and Troubled Past: He's doing quite well now, but he attempted suicide when he was a teenager and spent several years at a residential psychiatric treatment center, and at one point feared he might have HIV after his then-partner revealed that he was infected and had been sleeping around behind his back, which led to their breakup.
- The Fashionista: He's the mentor, after all.
- Harem Nanny: OK, so it's not exactly a Harem, and at that, it's a mixed one, but still, he definitely has the personality of one...
- Indy Ploy: Invoked by Tim Gunn to the contestants. Hence, make it work.
- Mentors: His main role is to offer feedback in the workroom.
- Major Injury Underreaction: "Well since leaving you only a few hours ago I had an altercation with a set of subway stairs, a trip to the emergency room, and four stitches. But I'm here for you!" Says Tim in his usual Tim Gunn cheerfulness with three deep cuts on his face.
- Nice Guy: He tries his best to give good advice to everyone, and even sympathises with the designers' troubles during home visits.
- Only Sane Man: He often has to give objective perspective when the designer needs this.
- Papa Wolf: Stated that he feels like the final 5-10 designers are like his kids, and he hates hearing them get torn apart by the judges.
- Sharp-Dressed Man: To the point the most "outdoor" he could get was a camouflage-printed suit.
- Silver Fox: He was named one of People Magazine's "Sexiest Men Alive" in 2006.
- Spin-Off: He had a short-lived makeover fashion show called "Tim Gunn's Guide to Style", where he helped women to dress better. Unlike other makeover shows, Tim actually helped the women to feel better about their sizes by dressing accordingly. Also heads the spin off Under The Gunn which involves past contestants mentoring another group of designers.
- Stern Teacher: As good advice as he gives, he also tells when something is not working, despite the dissapointment he gets.
- Stoic Spectacles: Tries his best to remain stoic in front of a designer.
- Straight Gay: Outside of his speak manners, he doesn't have many gay stereotypical behaviour.
- Team Dad: Many of the designers admire him or even look up to him as a father figure.
- What the Hell, Hero?: He's in charge of calling out designers who fall in this.
Judge and Fashion Designer In Seasons 1 to 10, making guest appearances in Seasons 11 and 12.
- Accentuate the Negative: Tends toward hilarious descriptions such as "she looks like a pole dancer in Dubai" or "this looks like a Handi-Wipe gone wrong".
- Big "NO!": Michael Kors have a particularly memorable one, which while not too loud on the volume front, definitely had the emphasis of one.
- Camp Gay: Very notable during his feedbacks full of quips
- Cool Teacher: In season 1, all the designers agreed that he was the most fair of the judges and his critiques were mostly dead-on.
- Cynical Mentor: In addition to pointing out flaws, he also adds some jokes about the designs.
- Deadpan Snarker: He is the judge in charge of making the cracks at the Bottom 3 expense.
- Hooker with a Heart of Gold: Michael Kors catch-all phrase for any particularly raunchy outfit. Sometimes couched in a film reference, as in "She looks like Shirley MacLaine in Irma La Douce".
- Limited Wardrobe: He always dresses the same: Black jacket, black t-shirt and jeans. Sometimes he varies it wearing white pants.
- Mad Libs Catch Phrase: He's fond of describing bad outfits with some variation of "She looks like a [mother of the bride/stripper/nun/waitress/Always Female occupation] on her way to a [funeral/disco/wedding/other event] in [geographic location]."
- Nobody Over 50 Is Gay: Averted, since Kors was born in 1959 and married his longtime partner in 2011 after New York State legalized gay marriage.
- Not So Stoic: In the Season 4 reunion special, a footage is shown where Michael just looses it when one of the models made a pelvic thrust and he couldn't stop laughing at all. Even Nina cracked when watching him.
- Put on a Bus: He's no longer in the judges panel starting season 11.
- Stern Teacher: Equally as snarky.
Judge and Fashion Editor of Elle Magazine
(Seasons 1 to 5) and Marie Claire Magazine
(from Season 6 onwards)
- Accentuate the Negative: Is prone to this, but without the humour.
- The Cameo: She appeared in one episode of Ugly Betty with Christian Siriano after season 4 was over.
- The Dreaded: When she appears as a guest judge during All Stars seasons, the designers tend to get very nervous.
- Fan Nickname: Fans on the street even called Nina once "Meana Garzilla".
- The Fashionista: Required since she's a fashion editor.
- Gratuitous Spanish: In season 8, Nina translated in perfect Spanish a question for Casanova.
- One Judge to Rule Them All: Ostensibly averted, but Nina Garcia is widely regarded as the key to the judging panel.
- Only Sane Woman: She has to argue with crack decisions and stubborn designers.
- Stern Teacher: To the point many designers are afraid of her, and consequently whenever she praises a designer's look that designer's face is almost guaranteed to light up.
Judge and Fashion Designer from Season 11 onwards.
- The Straight Man: Usually very basic and straightforward with his critiques with minimal joking unless an outfit really went the extra mile in bad. He can get jokier when alone with the other judges.