WASHINGTON — Twice a day, for breakfast and lunch, Benjamin R. Civiletti, attorney general to President Jimmy Carter, invited his seven special assistants — mostly young graduates of the nation’s most prestigious law schools — to his private dining room at the Justice Department for casual conversation or friendly debate.

Merrick B. Garland, fresh from a Supreme Court clerkship, 26 and looking years younger, showed little interest in chitchat. Even in staff meetings, he spoke so rarely that some colleagues figured him for shy or insecure.

But it became clear over time that Mr. Garland was silently working out his arguments, processing facts and testing alternatives. Surrounded by overachievers in a city full of people clamoring to be heard, he was waiting until he had something to say.

“He has a tendency to save up his points, and when he finally speaks up, his points come out almost like a Gatling gun,” said Lovida H. Coleman Jr., who worked with him back then and remains a close friend. “Not in an unpleasant way, not in a way of showing off. He was smart and to the point.”