By Tripp Mickle and Tim Higgins

Waymo LLC Chief Executive John Krafcik said he is stepping down from his role, bringing an end to the former auto executive's more than five-year tenure leading Google parent Alphabet Inc.'s autonomous-vehicle unit.

The company said Friday that it is promoting its chief technology and operating officers, Dmitri Dolgov and Tekedra Mawakana, to lead a decade-old effort to make self-driving cars a reality. They will share the title of co-chief executive.

After a long career working at companies including Ford Motor Co. and Hyundai Motor Co., Mr. Krafcik was brought into Google's project in 2015 at a time when the tech company was facing skepticism from car makers over its objectives and the possibility of a new rival. He spent time wooing industry leaders at auto shows around the world, trying to frame Waymo's effort as one to develop a car's driver and not one intending to build its own car. He did deals to work with Chrysler, Jaguar and the Renault-Nissan alliance.

Under his leadership, Waymo launched a limited ride-hailing service in suburban Phoenix where some customers are shuttled around in minivans without a person behind the wheel. The challenge of scale has remained, however, as deploying the technology has proven harder than many technologists expected.

The 59-year-old also led Waymo's conversion into an independent subsidiary of Alphabet and the raising of $3.25 billion of external funding, bringing on investors such as private-equity firm Silver Lake and Abu Dhabi's Mubadala Investment Co. "It's a long road getting this technology out to the world," Mr. Krafcik said during an interview with The Wall Street Journal last year.

In a blog post Friday, Mr. Krafcik said he would serve as an adviser to Waymo, adding that "Dmitri and Tekedra have my full confidence and support." He said that he will be going on a sabbatical with his wife and relocating to Austin, Texas, from Silicon Valley.

"He essentially turned Waymo into a real company," said Mike Ramsey, a Gartner automotive analyst. "They didn't hit some of their development targets, but nobody did. He turned what was a R&D effort into a commercial operation."

While Mr. Krafcik may have helped soothe some in the auto industry, his arrival in Mountain View, Calif. -- the city where Google is based -- ruffled feathers among some of the program's longtime engineers. Two of the highest-profile members of the team departed in the months after his arrival.

Engineer Anthony Levandowski left in early 2016 and the project's leader Chris Urmson, who had been chief technology officer, left in August 2016. Both would go on to found rival autonomous vehicle startups. Mr. Levandowski would later plead guilty to stealing trade secrets, while Mr. Urmson co-founded Aurora, which has emerged as one of Waymo's most formidable driverless vehicle rivals.

In their absence, Mr. Dolgov's profile grew as he assumed the role of CTO. He joined Google's self-driving car project when it began in 2009 and led the development of Waymo's autonomous system, known as Waymo Driver. He studied physics and math at the Moscow Institute of Physics and Technology before earning a doctorate in computer science from the University of Michigan.

Ms. Mawakana, a former senior public policy executive at Yahoo and eBay Inc., joined in 2017 to help navigate Waymo through the thicket of policy and regulatory issues that arise when trying to deploy robot cars. Her role continued to grow over the years with her becoming chief operating officer in 2019.

Waymo is changing its leadership during a period of heightened interest and competition in the auto industry. Inspired by Tesla Inc.'s surging valuation, several electric-vehicle upstarts have turned to the public markets for additional funding. Faraday Future, Arrival Group and Fisker have completed or are in the process of going public by merging with special-purpose acquisition companies, or SPACs. They have offered aggressive revenue forecasts, which some have had to revise after missing targets.

Waymo remains the leader in autonomy, with more vehicles on the road and operations than anyone else in the field. However, it faces challenges as it looks to expand its fleet of robotaxis to other cities. Waymo has to secure government approval to operate, persuade local citizens to ride and monitor performance as the vehicles navigate local roads.

"It's a slow creep to do everything city to city," Mr. Ramsey said. "It costs a lot of money and time."

It falls to Mr. Dolgov and Ms. Mawakana to define Waymo's strategy, expanding its footprint and refining its commercial plans. Mr. Ramsey said they will need to determine whether it will be a supplier of software to auto makers, a fleet provider that runs robotaxis or some other alternative.

Write to Tripp Mickle at Tripp.Mickle@wsj.com and Tim Higgins at Tim.Higgins@WSJ.com

(END) Dow Jones Newswires

04-02-21 1624ET