Mark Knoller, a White House radio correspondent for CBS News who meticulously tallied the activities of presidents, including how many times they played golf, read from a teleprompter and declared that they “will not rest” until finishing the job for the American people, died on Saturday in Washington. He was 73.

His death, in a hospital, was announced by CBS News, which said he had diabetes and had been in poor health.

Robust in size, with a booming voice and a married-to-the-job work ethic, Mr. Knoller was a beloved fixture on the White House beat for more than 40 years. He was known not just for his tough questions but also for his voluminous records of presidential minutiae, which he shared freely with other reporters.

“He was a stickler for fact and clarity and fairness,” Ann Compton, a former White House correspondent for ABC News, said in an interview. “When you cover the president, you cover everything from global crises to whether the president hates broccoli, and Mark relished all of that.”

Called “the savant of 1600 Pennsylvania Avenue” by one admirer, Mr. Knoller began keeping track of presidential statistics during Bill Clinton’s administration.