Amazon.com Inc. named a new sales chief for its cloud unit amid growing rivalry with Microsoft Corp. and Alphabet Inc.’s Google.

Matt Garman, a longtime Amazon Web Services engineering executive, will now oversee the cloud unit’s sales and marketing teams, according to a memo AWS chief Andy Jassy sent to employees on Friday. Garman will report to Jassy.

AWS’s previous marketing chief, Ariel Kelman, is leaving the company to “pursue another endeavor,” Jassy said in the note. An AWS spokesman declined to comment on Kelman’s destination.

Garman last month was named to Chief Executive Officer Jeff Bezos’s strategy-setting S-team, evidence of AWS’s growing importance to the e-commerce and technology company.

Garman previously ran the engineering teams responsible for Amazon’s rented computing power services, including the company’s foray into selling server racks to businesses. He joined Amazon in 2006, the year AWS launched its first major services, after finishing business school. Today, AWS is the biggest provider of rented infrastructure and data storage services; in the last 12 months the unit generated 12 per cent of Amazon’s revenue and a majority of operating income.

Rachel Thornton will take over Kelman’s duties. She, Teresa Carlson and Mike Clayville, leaders of AWS’s government and business sales groups, respectively, will report to Garman.

The S-team sets the Seattle company’s corporate priorities and features a powerful contingent of AWS executives, including Jassy, Charlie Bell, who oversees core engineering efforts, and Peter DeSantis, who leads data center infrastructure teams.

Amazon doesn’t comment publicly on the composition of the S-team, which is said to include about two dozen executives. The company has been criticized for a c-suite that skews whiter and more male than Amazon’s workforce and customer base.

The reorganization announced Friday also included a promotion for the leader of Amazon’s machine learning efforts. Swami Sivasubramanian will report to Bell. Previously, he reported to one of Bell’s deputies, Raju Gulabani, who leads AWS’s database engineering teams.