Kanye West and Adidas: How Misbehavior Broke Up a Lucrative Partnership

Adidas employees quickly discovered that Mr. West was brimming with ideas. They also learned that he operated unlike anyone they had ever encountered.

He could be enthusiastic to the point of creating chaos. Early on, he showed up unexpectedly at the Adidas office in New York with Ms. Kardashian and tens of thousands of dollars worth of sewing machines. It was so disturbing that he was sent to a studio across town. Once immersed in the design work, he was so obsessed with every detail that it was difficult to finish anything.

And he quickly became angry when frustrated. As the deadline set for Yeezy’s first fashion show in February 2015, he attacked, using sexually explicit language, Rachel Muscat – the rare female manager in a male-dominated industry – and other Adidas employees. Some complained of verbal abuse toward Adidas superiors, according to several team members. (Like some other current and former Adidas and Mr. West employees interviewed for this article, they spoke only on condition of anonymity because they are bound by nondisclosure agreements.)

However, attention quickly shifted to the show, where the shoes garnered praise. At that concert that night, Mr. West, Travis Scott and other rappers wore the new Yeezys, a preview of the promotion the artist and the personalities around him could generate for Adidas.

Released in limited series over the following months, the shoes sold out within hours, crashing servers and driving up prices on resale sites. They hooked sneakerheads, fashionistas and even athletes who had sponsorship deals with Adidas rivals.

First came a suede high-top, followed by the Yeezy Boost 350, a sleek sneaker inspired by Nike’s Roshe Run and dubbed “the Roshe Killer” by Adidas. It had a flat front, not the standard rolled toe that Mr. West disdained. It brought a Yeezy touch to Adidas innovations: Boost foam, new cushioning technology in the sole and a patterned knitted fabric on the upper. The shoe was not suitable for running or sports, but complemented the athletic clothing that was becoming fashionable.

“He questions everything, but he puts all his energy into how he questions it, and you see the results,” Nic Galway, one of Adidas’ top designers, said in a 2015 interview .

The 350 took top honors that year at the industry’s annual awards ceremony, considered the “Oscars of footwear.”

Taking the stage with Mr. Wexler, Ms. Muscat and Arthur Hoeld, a top Adidas executive, Mr. West acknowledged that he could be a difficult partner. “It’s cool to be here with the three people I’ve yelled at the most in the last year,” he said, beaming.

His tone changing, he later added: “Jon basically saved my life.”