Perhaps the only US President to promise to only run for one term (and stick to the promise)?

He has been called one the the least known best Presidents the country has had.

He was an unexpected winner of the Democratic nomination and of the Presidential election (running as a Democrat against Henry Clay of the Whigs).

He brought Texas into the Union. He threatened war with Britain over the Oregon Country, but worked a compromise which split the territory with Britain in the end. He led the nation into the Mexican American war which resulted in vast territorial gains.

Polk was a congressman, Speaker of the House, and Governor of Tennessee, before running for President.

Polk set four clearly defined goals for his administration:

Reestablish the Independent Treasury System. Reduce tariffs. Acquire some or all of Oregon Country. Acquire California and New Mexico from Mexico.

He achieved them all in one four year term. Did not run again (as he had promised when nominated), and died shortly thereafter of cholera.

All in all, one of the most interesting little known Presidents in American History.

Hope you have fun with him.