On January 20, 1949, Harry S Truman was inaugurated as the President of the United States, and the ceremony was televised for the first time in history. You can see his full speech here, courtesy of C-SPAN.
Truman was a former Senator from Missouri who had served as the third Vice President under President Franklin Delano Roosevelt for less than a yearr before assuming the presidency when Roosevelt died in 1945. He was expected to lose to Governor Thomas Dewey of New York, but managed to pull off an upset win, leading to the famous image of Truman holding up the erroneous Chicago Tribune headline "Dewey Defeats Truman."
President Truman's inaugural address became known as the Four Point Speech, boiling his administration's goals down to bullet points:
His term in office spanned the Korean War, escalated the Cold War, and thus saw his popularity plummet to near record lows, prompting him not to run for another term. He would be succeeded in office by Dwight. D. Eisenhower in 1953.
Andy Hunsaker has a head full of sitcom gags and nerd-genre lore, and can be followed @AndyHunsaker if you're into that sort of thing.