Kanye West and Adidas: How Misconduct Broke a Lucrative Partnership

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

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

And he was quick to anger when frustrated. Running up against the deadline for the first Yeezy fashion show in February 2015, he lashed out, using sexually explicit language, at Rachel Muscat — the rare female manager in a male-dominated industry — and other Adidas employees. Some complained about the verbal abuse to Adidas higher-ups, according to several members of the team. (Like some other current and former employees of Adidas and of Mr. West interviewed for this article, they spoke only on the condition of anonymity because they are bound by nondisclosure agreements.)

Attention quickly shifted to the show, however, where the shoes drew raves. Performing that night, Mr. West, Travis Scott and other rappers wore the new Yeezys, a preview of the promotion the artist and the high-profile people around him could generate for Adidas.

Released in limited runs over the next few months, the shoes sold out in hours, crashing servers and sending prices soaring on resale sites. They hooked sneakerheads, fashionistas and even athletes who had endorsement 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 nicknamed “the Roshe killer” inside Adidas. It had a flat front, not the standard rolled toe that Mr. West disdained. It put a Yeezy spin on Adidas innovations: Boost foam, a new cushioning technology, in the sole, and a patterned knit fabric on top. The shoe wasn’t suited for running or sports, but complemented the athleisure apparel that was coming into fashion.

“He challenges everything but he puts full energy into how he challenges it, and you see the results,” Nic Galway, a top Adidas designer, said in a 2015 interview.

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

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 up here with the three people that I’ve screamed at the most in the past year,” he said, beaming.

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