Which president was known as Old Hickory?

The president who was known as "Old Hickory" was Andrew Jackson.

To find the answer to this question, you could have used various sources such as history books, encyclopedia entries, or reliable websites dedicated to U.S. presidents. Andrew Jackson earned the nickname "Old Hickory" due to his tough and unyielding personality. This nickname refers to the tough wood of the hickory tree, symbolizing Jackson's strong and resilient nature.