|Harry S. Truman|
Harry S. Truman, showcased his ambidextrous talent when he threw out balls with both his right and left arm in 1950.
Opening Day History by Baseball Almanac
Truman threw out the first pitch in seven successive opening games in Washington between 1946 and 1952. President Truman was ambidextrous and used both arms during his numerous ceremonial pitches. Read more
(source: The SportsLifer)
Harry Truman was naturally left-handed.
McCullough, David. "Truman". p47 "Naturally left handed, he was taught [by his teachers] to use his right hand".
Harry S. Truman - 33rd President - The White House