Tim Cook’s final day as CEO marks the beginning of Apple’s next big test

Tim Cook’s final day as Apple’s chief executive officer marks the end of one of the most successful leadership transitions in modern corporate history, as the technology giant prepares to hand control to hardware chief John Ternus on September 1.

After 15 years as CEO, Cook will step down from the role he inherited from Steve Jobs in 2011 and become Apple’s executive chairman.  Cook may be leaving the CEO role, but he is not leaving Apple. As executive chairman, he will continue to support aspects of the company, including engagement with policymakers around the world. 

John Ternus, Apple’s senior vice president of Hardware Engineering, will take over as CEO, marking only the third major leadership era in the company’s modern history. 

Cook leaves behind a company that has become one of the most valuable businesses in history, with Apple’s market value rising during his tenure. Under his leadership, the company expanded beyond its dependence on the iPhone, building major businesses around wearables, services, and its wider ecosystem. 

From Steve Jobs’ successor to Apple’s empire builder

When Cook became CEO in August 2011, the biggest question was whether anyone could successfully replace Steve Jobs.

Jobs was widely regarded as one of technology’s greatest product visionaries. Cook, by contrast, was known primarily for his operational expertise and supply-chain management. However, Cook changed the definition of what successful leadership at Apple could look like.

Rather than trying to become another Steve Jobs, he focused on scaling Apple. The company expanded its global supply chain, strengthened its manufacturing capabilities, and…