New York CNN Business  — 

Amazon has appointed Tableau CEO Adam Selipsky as the new head of its biggest moneymaker, Amazon Web Services.

His hiring is part of a major leadership transition at Amazon (AMZN) after founder and CEO Jeff Bezos announced in February he would be stepping into the role of executive chair later this year, to be replaced as chief executive by Andy Jassy, the current head of Amazon (AMZN) Web Services. The ascension plan solidified the importance of AWS to the internet giant’s future — and raised big questions about who would take over leading it.

Selipsky spent nearly the past five years serving as chief executive of cloud data company Tableau, during which time the company’s value quadrupled before being acquired by Salesforce for $15.7 billion in 2019.

Before that, he held a number of senior roles at AWS. Selipsky was hired in 2005 as one of the business’s first vice presidents after it started just two years earlier, and ran sales, marketing and support at AWS for 11 years, according to a letter Jassy sent to AWS employees Tuesday.

Adam Selipsky has been appointed to take over as CEO of Amazon Web Services from Andy Jassy later this year.

Selipsky is not, however, among the several internal executives whom analysts had predicted might get the top job, including Matt Garman, AWS’s top sales and marketing executive.

“Adam brings strong judgment, customer obsession, team building, demand generation, and CEO experience to an already very strong AWS leadership team,” Jassy said in the letter. “And, having been in such a senior role at AWS for 11 years, he knows our culture and business well.”

Selipsky will return to Amazon on May 17, and spend several weeks transitioning before officially taking over the CEO role in the third quarter, according to Jassy’s letter.

He has big shoes to fill: Jassy oversaw the rapid growth of AWS for nearly two decades into a more than $50 billion business that contributes more than half of Amazon’s total income, and provides the backbone to much of the internet.

The growth potential for AWS is still huge, as more companies and government agencies move their data from on-premises servers to the cloud. But the cloud computing market has also gotten more crowded: Amazon now has to defend its outsized market share against increasingly fierce competitors, especially Microsoft (MSFT) Azure.

“It’s easy to forget that AWS is still in the very early stages of what’s possible,” Jassy said. “We have a lot more to invent for customers, and we have a very strong leadership team and group of builders to go make it happen. Am excited for what lies ahead.”

Brian Klingbeil, chief strategy officer at hybrid IT provider and AWS partner Ensono called Selipsky’s hiring “a smart move” by Amazon.

“It will be important to watch Selipsky’s strategic moves to match AWS’ pace with Azure, and even Google Cloud’s upward momentum,” Klingbeil said.