I understand that yes, there were two. George Washington hunted vampires from his mid-teen years. This is reflected in the story of his chopping down a cherry tree. The tree was actually used for stakes that he used to kill three vampires who were terrorizing the region.

Zachary Taylor was another vampire hunter. However, he was not as skillful as either Washington or Lincoln, and succumbed to a vampire in his third attempt at killing one, which was hushed up by Congress and passed off as a mysterious death after a brief illness. What they don't teach you in school is that the illness was actually a result of a bite and his death was the result of a staking by his White House staff to prevent the President's turning.

You can read about these two in Transylvanian historian Stanislaw Săpânţa's 1936 work "Lesser Vampiric Outbreaks on the American Eastern Seaboard".

Teddy Roosevelt was definitely a slayer.