Spade was born Katherine Noel Brosnahan in Kansas City, Missouri, the daughter of June (Mullen) and Francis (Frank) Brosnahan, who owned a road-construction company. She was of mostly Irish descent. After graduating from St. Teresa’s Academy, an all-female Catholic high school, Spade attended the University of Kansas. She later transferred to Arizona State University. She joined the Kappa Kappa Gamma sorority and graduated with a journalism degree in 1985, thinking she would go into television production. While in college, she worked in sales at Carter’s Men Shop, a men’s clothing store in Phoenix. It was there where she met co-worker Andy Spade, who later became her husband and business partner.

By 1986, the couple had moved to Manhattan. Kate worked in the accessories department at Mademoiselle magazine. She left Mademoiselle in 1991, achieving the rank of Senior Fashion Editor/Head of Accessories. While working for Mademoiselle, she had noticed that the market lacked stylish, affordable and sensible handbags and decided to create her own. “I wanted a functional bag that was sophisticated and had some style,” she would recall.

Kate and Andy founded Kate Spade New York in January 1993. Spade was initially undecided on the brand’s name, because she and Andy had not yet married, and “Kate Brosnahan” seemed a cumbersome name for a fashion label. She considered a number of names, but agreed when Andy suggested “Kate Spade”, as she would take the name Spade after their marriage.

Spade married Andy Spade, the brother of actor/comedian David Spade, in 1994. They had separated a few months before her death.

The company exclusively sold handbags at first, but soon expanded to clothing, jewelry, shoes, stationery, eyewear, baby items, fragrances, and gifts. In 1996, the Kate Spade brand opened its first boutique, a 400-square-foot (37 m) shop in Manhattan’s trendy SoHo district, and moved its headquarters into a 10,000-square-foot (930 m) space in West 25th Street.

In 1996, the CFDA awarded Spade “America’s New Fashion Talent in Accessories” for her classic designs. In 1998, the organization again honored her for “Best Accessory Designer of the Year”.

In 1999, Spade sold a 56% stake in her business to Neiman Marcus Group, helping to expand the brand worldwide.

In 2004, “Kate Spade at home” was launched as a home collection brand. It featured bedding, bath items, china, wallpaper, table decor, flatware, and various decoration items. A Kate Spade store was opened in Aoyama, Tokyo, Japan.

Her home collection won her three design awards in 2004, including, House Beautiful’s “Giants of Design Award for Tastemaker”, Bon Appétit’s “American Food and Entertaining Award for Designer of the Year”, and Elle Decor’s “Elle Decor International Design Award for Bedding”.

The couple had one child, Frances Beatrix Spade, born in 2005.

By 2006, Spade had sold her remaining 44% shares to Neiman Marcus Group. The Group sold the label in 2006 to Liz Claiborne Inc., for $124 million; it was later renamed Fifth & Pacific. The company was later purchased by Coach, Inc. in May 2017; both Coach and Kate Spade are now part of Tapestry, Inc.

In 2016, she launched a new collection of luxury footwear and handbags under the brand name Frances Valentine. The name stemmed from a hybrid of family names; Frances is a family name on Spade’s paternal side. “Valentine” was Spade’s maternal grandfather’s middle name, having been born on Valentine’s Day. Spade later legally added Valentine to her full name.

In 2017, she was inducted into the Entrepreneur Hall of Fame at the Henry W. Bloch School of Management at the University of Missouri, Kansas City.

Also in 2017, she was named one of the Most Creative People in Business by Fast Company.

A housekeeper found Spade dead in her Manhattan apartment on June 5, 2018. Her death was ruled a suicide by hanging. Police reported she had left a note addressed to her daughter. The day after his wife’s death, Andy Spade released a statement: