Mark Knoller, a veteran CBS News correspondent known for his meticulous coverage of U.S. presidents, has died at the age of 73. His cause of death remains undisclosed, though he had been battling diabetes and was in poor health.

Knoller, who joined CBS News in 1988, earned the nickname “the Wikipedia of the White House” for his exhaustive documentation of presidential activities. Colleagues described him as a dedicated journalist who maintained detailed records of every presidential action, speech, travel, and public appearance. His work spanned eight presidential administrations, from George H.W. Bush to Donald Trump.

Friends and peers praised Knoller’s relentless work ethic and commitment to factual reporting. Tom Cibrowski, president and executive editor of CBS News, called him “the hardest-working and most prolific White House correspondent of a generation.” Weijia Jiang, president of the White House Correspondents Association, noted he was “the heart and soul of the White House press corps,” admired for his passion and reliability.

Knoller left CBS in 2020, citing being laid off. His legacy includes a lifelong dedication to chronicling presidential history, a task he undertook independently due to the absence of a centralized database. Colleagues remembered him as a trusted figure who balanced professionalism with humor, leaving an indelible mark on American journalism.