In the beginning of each season I would sit down with my team and we would talk about all the characters, and whatever information I had at the time we would discuss in terms of costume design. And then we would start researching. I allotted a week’s time to research and to complete the design book – in the beginning of each season I would create a design book for each character. In a total of five weeks that I get to prep the season, a week is a good amount of time. The preparation period goes really fast.

And then, throughout the season, my team and I, we are always researching. Because new characters will come into play or I’ll be thinking about something specific for one of the principal casts, and want to be able to show something specifically, visually to the team or Matthew Weiner. - Janie Bryant, Mad Men Costume Designer (x)

‘Mad Men’ Costume Designer Janie Bryant’s 7 Favorite Outfits

When Rachel Showed Up

“Rachel Menken was the first fashion-forward character on ‘Mad Men,’ ” said Ms. Bryant, referring to an early love interest of Don’s who headed up the fictional Menken’s department store. “She was going to Paris every season to buy clothing for that store. She was a woman who always had every outfit perfectly put together; someone who would wear Chanel and everything couture. This outfit is a representation of everything that she is.”

Two vintage Carolee pearl and rhinestone necklaces belonging to MadMen stylist Janie Bryant. Striking on their own, combined they become the ultimate statement necklace. Bryant recommends layering strands of pearls, belting a scarf or long chain with a pendant, or using a brooch as a hair clip – in short, extending the lives of accessories by making them cross over into different decorative functions. Photo from The Fashion File: Advice, Tips and Inspiration from the Costume Designer of Mad Men.

If there’s one woman who should be credited with turning actor Jon Hamm into Don Draper, television’s most dashing heartthrob, it’s Janie Bryant. As the costume designer for the AMC series “Mad Men,” Ms. Bryant is the sartorial mastermind behind the show’s exquisite suits, freshly polished shoes and perfectly positioned pocket squares. “The secret is impeccable tailoring,” said the Tennessee native, who earned an Emmy for her work on HBO’s “Deadwood” series (she’s up for another for “Mad Men” this fall). “Don is all about secrecy, so the palette is very minimal and masculine.”

Last week Ms. Bryant unveiled a collaboration with Banana Republic for a limited-edition collection featuring 65 pieces for men and women that evoke the show’s characters, including 1960s-inspired circle skirts (Betty), leopard trenches (Joan) and, of course, fitted retro suits (Don). “Janie has an amazing passion for costume design,” said Simon Kneen, creative director of Banana Republic. “That polished ‘Mad Men’ look has inspired a lot of designers.” Indeed, to look at fall’s over-the-knee pencil skirts, nipped waists and bespoke suits is to dream up a boardroom scene at Sterling Cooper.

Next up, Ms. Bryant, who authored the recent style-advice book “Fashion File,” is at work on the highly anticipated fifth season (yes, filming has finally begun!) in which the cast eases into the late '60s (sorry, she won’t divulge any spoilers). If the Drapers do shimmy into the pre-Disco era? “I’m into the whole '70s thing,” she said. “The flared jeans, wide-legs—I love all those hats.” We caught up with the Los Angeles resident between fittings on set.

I love dissecting moviesscene by scene for inspiration. “The Apartment” and “Days of Wine and Roses” were huge influences. For the beginning of “Mad Men,” which was all about the late '50s, I watched Alfred Hitchcock’s “North by Northwest” over and over.

My grandmother was a huge inspiration for the Betty Draper character. She was an impeccable hostess. She loved sterling and fine china and made aprons for every single outfit that she wore.

The trick to gettingthat hourglass shape is wearing proper undergarments.Maidenform’s thigh slimmer is incredible. They also have an amazing black slip with a built-in bra that’s sexy and controlled.

For inspiration, I love looking at old Time or Look magazines. Also, family photos are so informative because that is really how people wore their clothes.

The '90s was my least favorite fashion era. All those oversized things and guys wearing pants below their butts—it was the beginning of nondressing!

My favorite hotel is the Mount Nelson Hotel in Cape Town. They have the most magnificent teatime in the whole world.

My latest obsession is the French Baroque period. I love all the wigs and that the men were even fancier than the women. My dream is to design a film like “Dangerous Liaisons.”

I collect vintage sweetheart bracelets.Young men used to give them to their sweethearts when they would leave for the military or war.

The most magical city is Ouarzazate, Morocco. They filmed “Lawrence of Arabia” there. The markets sell raw amber, which you can put on your pillow at night or rub on your wrist for perfume.

My all-time favorite vintage store is Playclothes in Burbank. My mom and I also love Treasure Island in Naples, Fla. It’s in a strip mall and sounds like the corniest place ever but I find the most incredible fur pieces there. If you want to buy vintage fur, go to Florida.

I never leave the house without putting on makeup. I’m obsessed with Tom Ford’s coral lipstick and Maybelline’s Great Lash mascara.

The most challenging episodes are always the biggest. There are so many restaurant and club scenes. “My Old Kentucky Home” was huge. Every single person had to be fit, have alterations—and it had to all work together.

My most treasured vintage piece is a custom-made purple, gold and bright pink brocade lace '60s cocktail dress with mink fur trim at the cuffs. It was $75.