I've been reading The End of Money, a book packed with tidbits about the history of money, with a special focus on the greenback. The book mentions former Secretary of the Treasury Salmon P. Chase, who was in the enviable position of designing the original US $1 bill in 1862. So who do you think he put on that bill? Himself, of course. Chase wanted to be President, and he figured that having his face on popular currency would be killer buzz-marketing -- obviously, that didn't pan out. Above is a (suitably low-fi and non-counterfeity) image of that first dollar bill, courtesy of Wikimedia Commons.
Chase's visage also graces the obverse of the 1929 $10,000 bill, as a kind of consolation prize for his demotion from $1 fame. Other relevant fun facts: the "P" in Salmon P. Chase stands for "Portland"; Chase National Bank was named after him (though he wasn't actually involved in its operation); and in 1869 George Washington replaced Chase on our $1 notes -- by that time, Chase was a member of the Supreme Court, busily declaring his own creation of the greenback to be unconstitutional. You had a good (seven-year) run, Salmon.