A senior Tesla Inc. executive, who was the company’s main technical contact with U.S. safety investigators, has left for rival Waymo LLC, according to people familiar the decision.

Matthew Schwall, who had been the director of field performance engineering at Tesla, exited the company as the National Transportation Safety Board has been investigating multiple crashes involving the electric vehicles. Mr. Schwall’s exit coincides with Tesla’s announcement Friday that its engineering chief, Doug Field, was taking a leave of...