Fred Ryan, the publisher and chief executive of The Washington Post, told employees on Monday that he was stepping down, ending his nearly decade-long run as the newspaper’s top business executive. He was appointed by Jeff Bezos, the founder of Amazon and owner of The Post.

In a note to staff, Mr. Ryan said that his next job would be leading the Center on Public Civility, a new project by the Ronald Reagan Presidential Foundation and Institute that is backed by Mr. Bezos.

“Today, the decline in civility has become a toxic and corrosive force that threatens our social interactions and weakens the underpinnings of our democracy,” Mr. Ryan, 68, wrote in the memo. “I feel a strong sense of urgency about this issue.”

Mr. Bezos thanked Mr. Ryan for his service in a separate note to employees, saying he led the newspaper through a period of “innovation, journalistic excellence and growth.” He will remain publisher for the next two months.

Patty Stonesifer, the former chief executive of Martha’s Table, a provider of food and clothing for low-income people, will be The Post’s interim chief executive, Mr. Bezos said.

“You’ll soon see for yourself why I admire her,” Mr. Bezos said. “Her skills, judgment and character all stand out. She also understands the importance of our mission and has a deep respect for the work we do here.”

This is a developing story. Check back for updates.