Herbert Hoover gained fame as director of the United States Food Administration and then the American Relief Administration during World War I. He ran for the presidency in 1920, but his candidacy fizzled when he lost to Senator Hiram Johnson in his own state’s Republican primary. Hoover campaigned loyally for Harding, and the president-elect gave him his pick of two cabinet positions. Hoover chose Commerce over Interior. Harding nominated Hoover on the day he was inaugurated, sending Hoover’s name to the Senate on this sheet of paper:
Hoover revolutionized the Department of Commerce (you can read about his efforts here, though the obligatory caveats about Wikipedia apply). He stayed on board after Harding’s death and until August 1928, making him the longest-serving Secretary of Commerce since Commerce and Labor were decoupled in 1913. He was the last surviving member of the Coolidge administration. No cabinet member since Hoover has later served as president, and no president since Hoover has won the office without prior electoral or military experience.
My own Hoover autograph: