Hundreds of Facebook Inc. employees have expressed outrage about a top global policy executive’s decision to support Supreme Court nominee Brett Kavanaugh and appear at his hearing last week, people familiar with the matter said.

Employees raised the question directly to Chief Executive Mark Zuckerberg during his weekly question-and-answer session last Friday, the people said. Chief Operating Officer Sheryl Sandberg also weighed in on the controversy on Friday in an internal discussion thread that has so far drawn hundreds...