Rall was probably born as a so-called "soldier child" ca. 1725. He was a son of Captain Joachim Rall from Stralsund, who served in the regiment of Major General Donop. The first mention of Johann Rall was as a new cadet of the same regiment on March 1, 1740, commanded at this time by Colonel Prince Casimir von Isenburg of Isenburg-Birstein.