Bozoma Saint John stole the show at Apple’s annual developer conference in 2016, injecting some cool into a sea of dad-dancing during her presentation on the company’s music-streaming service.

Last month she joined Uber as the company’s first chief brand officer, with a remit to “change the perception of the brand”. The company is in desperate need of an image overhaul after months of allegations of toxic work culture, sexual harassment and a series of high-profile executive departures, including that of the bad-boy chief executive Travis Kalanick.

Saint John has years of experience honing the reputations of multinational companies, but is shifting people’s perceptions of the ride-sharing company a challenge too far?

“It’s definitely a move in the right direction [for Uber],” said Adriana Gascoigne, CEO of Girls in Tech. “Saint John would provide incredible value at any tech company she joins because she has a stellar background.”

Saint John’s appointment at Uber makes her something of a unicorn in Silicon Valley: she’s one of a handful of black female C-level executives in tech, which in itself sends a message that Uber wants to shift away from its reputation as a misogynistic frat house.

“To me, there’s no sense of tokenism because I know I can do the job – I’m qualified to do the job, I can do a great job,” she told the New York Times. “Being present as a black woman – just present – is enough to help exact some of the change that is needed and some that we’re looking for.”

Saint John was born in the US, but spent her early years in Kenya and Ghana before the family returned to the US when she was 12. After graduating from Wesleyan University, she took a job at Spike Lee’s advertising agency, where she forged a relationship with Beyoncé that eventually led to her inking several promotional deals between Pepsi and the singer. These included a $50m deal to sponsor Beyoncé’s 2012 tour and 2013 Super Bowl halftime performance.

Bozoma Saint John at Apple’s Worldwide Developers Conference in 2016.

Shortly afterward, her husband, Peter, died from cancer. She and her daughter relocated from New York to Los Angeles, where she started a new role and fresh chapter of her life at Beats, the headphone startup founded by Dr Dre and the record producer Jimmy Iovine.

Four months later, she became an Apple employee, after the tech giant acquired Beats for $3bn. She climbed the ranks to become global head of marketing for Apple Music and iTunes.

While Saint John is a highly skilled marketer, Uber’s troubles run deep.

“Uber is feeling the dramatic effects of HR negligence. This deficit has slowly chipped away at the core values of the company so that tech workers no longer want to work there, and drivers think twice about driving for Uber,” Gascoigne said.

It will be very difficult to fix Uber’s brand image without changing the culture first, added the Bay Area communications veteran Ed Zitron.

“Marketing is usually an outward-facing job, so she’s not in a position where her direct remit is making sure the culture changes,” he said.

That requires widespread changes to management and hiring practices, led from the very top. Uber, valued at $69bn, has pledged to do this, under the guidance of its board member Arianna Huffington, who has emerged as the public voice for addressing Uber’s litany of scandals. One of Huffington’s achievements has been to lure executives such as Saint John.

“I profoundly believe that because real change rarely happens without a catalyst and a crisis, from the crucible of the last few months, a new Uber will emerge fueled by empathy, collaboration and putting people first,” said Huffington at an all-staff meeting in June.

However, the company has yet to appoint a new CEO, and there are several other leadership vacancies that need filling. Saint John will have to work with the rest of the C-suite to address poor management and hiring practices and embed these new values throughout the 12,000-strong team and corporate structure.

According to Uber’s diversity report, released in March, women account for 22% of leadership positions at the company. From a race perspective, the workforce is predominantly white (49.8%), with 30.9% Asian, 8.8% black, 5.6% hispanic and 4.3% multiracial employees.

At the same time it released the report, Uber pledged $3m over three years to support organizations working to bring women and underrepresented groups into tech, although it’s not yet clear how this money will be spent.

“We’re committed to making Uber a great place to work, no matter where you come from,” said the company.