As the song notes, elected President in 1844, James K Polk of Tennessee came into office with four goals each of which he accomplished over the next four years:
Acquiring the territory that became the American Southwest which he did by provoking and winning a war with Mexico.
Getting Britain to give up its claims in the Pacific Northwest, an area it was jointly administering with the United States, adding what became the states of Washington, Oregon and Idaho to the country and ensuring that Microsoft and Starbucks are not Canadian companies.
Lowering tariffs, paving the way for a flood of low-cost transistor radios from Japan in the 1950s and 1960s.
Establishing an independent treasury to fund the operations of the government, a solution which stayed in place until the establishment of the Federal Reserve in the early 20th century, a move which its proponents said would bring an end to the wide fluctuations in economic conditions seen in 19th century America which is why . . . oh, sorry about that.
Having accomplished his goals, Polk declined to seek a second term, returned home to Tennessee and died three months later.