The first Smith, and one of the, oh, four or five candidates for "most powerful tinker in history." He can usually figure out how to make any mechanical device work, including any mechanical device made by another tinker, then come up with his own solutions.
He first demonstrated powers including making tanks run on water with a splash of oil. (This was in WW2), then spent the 50s touring the earth, getting married, and having kids, one of whom ended up as his sidekick and the second Smith. Is unambiguously Lawful Good, and has faith in God that this will actually work out, which it does for him bizarre often.
He is the only member of the Atlantic Six ever to die of natural causes.