Hail to the Chief of Staff

When he became the head of Bloomberg in 2008, he brought the position with him. He is now the head of Sidewalk Labs, an organization owned by Alphabet, the parent company of Google. His chief of staff is Nate Jenkins, who was previously a chief of staff in the Office of Management and Budget at the White House.

”It’s the best leadership course you could potentially take,” Mr. Jenkins, 37, said of the role. (He was on the same phone call as Mr. Doctoroff.) “It expands my original capabilities. I am expanding how I both take in information and make decisions.”

Like the creative director, the position du jour about a decade ago, chiefs of staff can be powerful, or not. They can be among the leaders of a company, or not. Frequently, they are not actually in charge of staff. They can be on the executive team, off the executive team, or, like Mr. Amenta at Spring, “straddling the executive team.”

They are often former executive assistants. Beth Kurteson joined Winklevoss Capital in 2013 as an assistant and became chief of staff in 2014. Now she is the “managing director of operations, people strategy & growth.”

“No chief of staff is the same,” Mr. Amenta said.

There are similarities, though. Chiefs of staff tend to help field and minimize their principal’s duties. They often mediate between that person and the rest of the world. Mr. Doctoroff called his chiefs of staff a “conduit.”

“Generally the chief of staff is a foil to the principal, to supplement him or her,” said Dennis Yu, 35, a two-time chief of staff, first at Betterment, an investment app, and now at Chime, a banking app.