In terms of casting models, Prada (and its little sister brand, Miu Miu) may not be a pioneer in the way that say, Raf Simons is, as the Belgian-born designer quite famously started street casting his models from local Antwerp hang outs in the mid-1990’s. The result was a noticeable shift in aesthetic; skinnier, younger, paler boys than the agency-represented models that we were accustomed to seeing.

The Milan-based house under the direction of Miuccia Prada is also not a Givenchy. The Paris-based house and its creative director, Riccardo Tisci, and his casting team, are known for embracing a diverse notion of beauty (think: men (as opposed to boys) for S/S 2015, an array of ethnically diverse girls for S/S 2014, and transgender model, Lea T, for a handful of its shows and its F/W 2010 campaign). It is also not a Hood By Air, which notoriously casts even more unusual models, such as Boy Child. Having said this, Prada is the design house that comes to mind when thinking of new faces.

For 15 years, Prada’s casting could be attributed to master model maker, Russell Marsh, of whom the Telegraph described as having the “ultimate influence in the modelling world – a turn on the Prada catwalk seals a career – and Marsh has launched some of the most successful models in the business, including Lara Stone, Daria Werbowy, and Gemma Ward.” (And don’t forget Sasha Pivovarova and Arizona Muse). Well, the London-based publication is right, and the Prada runway is the ultimate launching pad for a successful career.

The logistics at Prada have changed a bit. After 15 years with the house, Marsh went freelance in 2013, and has since been working for the likes of Céline, Christopher Kane, Jonathan Saunders, Dries Van Noten and Marni. Prada hired American director Ashley Brokaw for its Fall/Winter 2012 show and she has stayed on board ever since.

New York Magazine’s The Cut summed up the varying preferences of the two directors quite well, writing: “While Marsh might be best known for booking more muted, contained-type beauties (think Eastern European, and more recently, Scandinavian) for Prada, Brokaw tends to favor a slightly harder, more mature, kind of tomboy aesthetic for her shows — think Aymeline Valade and Milou van Groesen.”

This is all to say that the casting of a Prada show is undeniably influential. A few examples. Daria Werbowy, who currently holds the record for opening and closing the most shows in one season (in addition to landing almost every major campaign; think: Céline (repeatedly), Salvatore Ferragamo, Balenciaga, Versace, Balmain, YSL, Dior, etc.), was named named the face of Prada during her debut season.

Arizona Muse walked exclusively for Prada in September 2010 and was subsequently named the breakout star of the season; she has since appeared in a handful of Louis Vuitton, Tiffany & Co., Chloe, and Jil Sander campaigns, among others, as well as Prada’s S/S 2011 campaign. Lindsey Wixson, who opened the Fall/Winter 2010 Miu Miu show and walked for Prada beginning in S/S 2012, has gone on to land YSL, multiple Chanel, multiple Miu Miu, Versace, and Alexander McQueen campaigns.

Sasha Pivovarova hardly needs an introduction. Amanda Murphy opened Prada’s Fall/Winter 2013 show. She now resides on’s Top 50 list and fronts campaigns for Prada, Celine, Salvatore Ferragamo and Bottega Veneta.

And more recently, 17-year old Maartje Verhoef, who opened Prada’s S/S 2013 show as an exclusive, booked the corresponding Prada campaign, as well as two Valentino campaigns, was reportedly the most in demand model of the recent S/S 2015 fashion month. This is just a small handful of the many Prada exclusives and doesn’t even take the boys into account, many of whom have similar post-Prada success stories.

There is a pattern here. Prada doesn’t just produce models. Its stamp of approval produces fashion industry stars, arguably in a more frequent manner than just about any other design house. With this in mind, what other houses can compete? In 2011, New York Magazine posited that maybe Balenciaga had the power to match up.

Acknowledging that “landing a Prada catwalk exclusive is widely considered to be the holy grail of runway bookings, turning an unknown face into one to watch in an instant.” The publication noted, “Balenciaga started booking exclusives, as well, and the label’s reputation for brilliant casting has begun to rival Prada’s.” While the Paris-based design house did not make a formal statement about exclusives this season, industry veteran Sasha Pivovarova appears to have walked exclusively for Balenciaga.

But what about Saint Laurent? Under the direction of Hedi Slimane, the Paris-based design house, which enlists the services of casting directors Barbara Nicoli and Leila Ananna, has been booking exclusive models each season. For its S/S 2015 show alone, the house landed six exclusive girls – all new faces. Dazed referred to its as a continuance of the house’s “cult casting.”

Not unlike the house’s founder, who was known for casting that flew in the face of the prevailing look of the day (then, this took the form of ethnically diverse models when the standard was all-American beauties), Slimane goes to extremes. Hailed for his ultra-skinny tailoring during his tenure at Dior Homme from 2000-2007, Slimane has returned to his famed aesthetic, and with it, pin-thin models, many of whom are somewhat androgynous-looking musicians and new faces.

You may recall that for his much-hyped Saint Laurent debut, the designer cast a handful of relatively unknown models as exclusives and worked with them daily during the weeks before the show. This has continued. For his F/W 2013 menswear show, wrote: “The model casting? Unheard-of indie band members from England, France, and the U.S.”

A few examples: Louise Parker, for one. The model, who told New York magazine that she was working a few relatively small gigs in New York before landing a Saint Laurent exclusive for Spring/Summer 2o13. She has since landed Topshop, Calvin Klein, Adidas and other big-name campaigns, covered Vogue Spain, and consistently walked for Chanel, Giambattista Valli, Dior, and Versace, among others.

As for why she landed an exclusive spot, Parker, a Minnesota native, said: “I know that Hedi likes American girls. He lives in L.A., and he loves that L.A. look. Most of the other girls who were exclusive were American. I also know that he loves long hair.”

Next up: Sarah Engelland. The Nashville-born teen walked exclusive for Saint Laurent for Spring/Summer 2013 as a brand new face. Since then she/s booked Yohji Yamamoto, Vivienne Westwood, John Galliano, Rochas, and Louis Vuitton – among others, and campaigns for Jill Stuart and Costume National. One more: Helena Severin, who walked exclusively in the house’s Spring/Summer 2014 show as a new face. She has subsequently landed a Dior campaign, and walked for Prada (numerous times), Celine, Louis Vuitton, Dior, Margiela, Valentino, etc.

And then there is Grace Hartzel (pictured above). The model opened and closed Saint Laurent’s Fall/Winter 2014 show as an exclusive and fronts its Pre-Fall 2014 and Fall/Winter 2014 campaigns. She also served as Slimane’s fit model for the season. She has become quite a favorite.

Grazia wrote on the topic: “The model has racked up a prolific portfolio at the brand in a very short space of time, quite unheard of for a relatively ‘unknown’ face.” Interestingly, the American teen had an impressive career prior to her Saint Laurent casting, but arguably only rose to fashion fame after Slimane named her his muse. The Fashion Spot noted: “Grace Hartzel walked the runway for Saint Laurent for the third season in a row — but this time, she’s getting tons of attention for it.”

In March, the Guardian further commented on Slimane’s penchant for the new face: “Even the model opening the show was key. She also closed the show wearing a red sequined party dress. Called Grace Hartzel, her name probably wasn’t known to most people in the room – which is exactly the way Slimane likes it.”

There is something that may prevent Saint Laurent from rising up to meet the challenge posed by Prada; the one potential downside of being a model on Saint Laurent’s radar is a lack of versatility that may be what attracted YSL in the first place. It is no secret that the Saint Laurent girl or boy is skinny – not model thin, so to speak – skinny. Slimane’s models are some of the skinniest in the business, which tends to be a bit too small for an array of other houses. In fact, they, along with the clothes often make headlines.

On the heels of the brand’s January 2013 menswear show, a publications of publications commented on the “shockingly thin” models. The Guardian, for instance, wrote: “Cheekbones were hollow, shoulders were slight and legs, encased in leather or artfully ripped jeans, were shockingly twig-like.”

In March, Shannon Bradley-Colleary, a body image blogger, launched a petition to convince Yves Saint Laurent’s CEO Francesca Bellettini to stop using “seemingly malnourished” models in the brand’s advertising campaigns. It gained quite a bit of traction. The British Advertising Standards Authority received complaints stemming from Saint Laurent’s Spring/Summer 2014 ad campaign and its “unhealthily thin” models. The ASA subsequently gave the campaign the OK.

Is this a total deal breaker for Saint Laurent’s models? Obviously not, based on the success that a handful of Saint Laurent exclusives (including Hartzel) have had in the industry.