Uber and its investors are facing a backlash over Travis Kalanick’s departure as chief executive — particularly from employees.

Starting late Wednesday, Uber employees circulated a petition asking the company’s board of directors to bring back Mr. Kalanick in an active role. More than 1,000 employees clicked to support Mr. Kalanick’s return in that capacity. In addition, Uber workers took to social media to express their dismay at the departure of Mr. Kalanick, who helped found Uber and made it a transportation behemoth.

“He worked day and night in creating this company to what it is today,” the petition said.

The reaction followed a tumultuous few days at Uber. Late Tuesday, Mr. Kalanick, 40, said he would step down as Uber’s chief executive after a coterie of investors — including Benchmark, one of the company’s biggest shareholders — pushed for him to resign. They acted after months of controversy at Uber over legal and workplace issues, including sexual harassment claims, which have prompted firings, investigations and promises to reform.

Mr. Kalanick’s resignation stunned many in Silicon Valley who viewed his position as secure, because he holds plenty of Uber’s stock and because he built the ride-hailing service into a nearly $70 billion company in just eight years.