The designer, who is believed to be in her late 40s, was found by her assistant and there was no immediate suspicion of foul play though the Medical Examiner has not yet released the formal report.
There was little to cause suspicion ahead of the shattering discovery, as her official Twitter account was updated at 11am- an hour after her body was reportedly found.
Tragic: L'Wren Scott, who has been romantically linked to Mick Jagger since 2001, was found dead in her Manhattan apartment on Monday morning
Suicide: Mick Jagger's model & designer girlfriend L'Wren Scott was found dead inside her Eighth Floor apartment at 200 Eleventh Avenue around 10 am on Monday
The Mormon-raised designer has been romantically linked to the Rolling Stones frontman since 2001.
Jagger is believed to be in Australia on tour with the band and has not released any statements in connection to the news.
Scott first broke into the fashion industry as a stylist before launching an eponymous line in 2006 that was a major hit with celebrities.
Fans including Oprah Winfrey, Nicole Kidman and Michelle Obama. She had even been tipped to design Angelina Jolie’s wedding dress.
Statuesque: The 6-foot-4-inch former stylist launched an eponymous line of her own in 2006 (pictured left in 2012 and right in 2010)
She continued to widen her brand and at the end of last year, she launched a collaboration with Banana Republic, starring alongside models in the ads.
L’Wren Scott was born and raised in Roy, Utah by her Mormon parents and graduated high school in 1985.
She stood at 6ft4in tall and caught the eye of celebrity photographer Bruce Weber who advised that she move to Paris to pursue a career as a model where she went on to work for Thierry Mugler and Chanel.
Then in the 1990s she moved to California and established herself as a stylist which led her to work closely with photographer Herb Ritts and Karl Lagerfeld. She has styled many celebrities including Madonna, Julia Roberts and Tom Hanks.
She launched her first designer collection, named Little Black Dress, in 2006.
L’Wren also worked styling costumes on film sets including Ocean’s Thirteen, Eyes Wide Shut and Shine a Light, a Martin Scorsese documentary about the Rolling Stones.
Her designs are said to be so flattering that she once told the Sunday Times that wearers have no need for Spanx.
It is perhaps for this reason that her creations have become beloved by curvier stars including Christina Hendricks and Oprah Winfrey – and both Penelope Cruz and Amy Adams wore L’Wren Scott gowns when they attended the 2011 Academy Awards as new mothers .
Fans also include Michelle Obama and Nicole Kidman.
Explaining her sexy aesthetic, she told Harper’s Bazaar that she designs with men in mind.
'Guys understand a waistline. They understand a silhouette. I dress for men. I have to feel good, you know what I mean?'