Presidents James Garfield and William Henry Harrison executed not a single presidential clemency action while in office, both having died before serving even one year of their terms.

Washington and Adams granted 16 and 21, respectively; Wilson and Truman's pardons each topped 2,000; Reagan granted 406 and Clinton, 456.

Source: University of Pittsburgh School of Law


Bonus Question:
Which President signed the most clemency actions?

Answer: 
Franklin D. Roosevelt signed 3687 clemency actions during his 12 years as President.