Ioannis Theofilakis competed in all five of the shooting events: military rifle, free rifle, military pistol, rapid fire pistol, and free pistol. In 1896 he competed in two rifle events. In the military rifle, he was placed ninth, with a score of 1,261. In the second string of 10 shots, he scored 312. His score and place in the free rifle event is unknown, except that he did not win a medal. For the 1906 Olympics there are currently no records found on his achievements, except that he did not win any medals. In the 1908 Olympics he participated in four events: men's team free rifle, where he placed ninth; men's team military rifle, where he placed seventh; men's individual pistol, where he placed twenty ninth; and men's team pistol, where he placed seventh. In the 1912 Olympics he participated in eleven events: 25 m team small-bore rifle, where he placed fourth; 50 m team small-bore rifle, where he placed fifth; 30 m team military pistol, where he placed fifth; team rifle, where he placed seventh; 50 m rifle, prone, where he placed thirty-second; 600 m free rifle, where he placed thirty-fourth; 300 m military rifle 3 positions, where he placed seventy-fifth; 25 m small-bore rifle, where he placed twenty-first; 100 m deer single shots, where he placed twenty-ninth; 50 m pistol, where he placed eighteenth; and 25 m rapid fire pistol, where he placed twenty-third. In the 1920 Olympics he participated in eleven events: 50 m free pistol, where he placed tenth; 50 m small-bore rifle unknown; 300 m rifle 3 positions unknown; 600 m military rifle prone, where he placed fourth; 300 m team military rifle prone, where he placed eleventh; 600 m team military rifle prone, where he placed seventh; 50 m team small-bore rifle, where he placed tenth; 300 m team military rifle standing, where he placed thirteenth; 50 m team free pistol, where he placed fourth; team free rifle, where he placed thirteenth; and 30 m team military pistol, where he placed second. At the age of 48 in the 1924 Olympics he participated in four events: team free rifle, where he was placed twelfth; 25 m rapid fire pistol, where he was placed fortieth; 50 m rifle prone, where he was placed forty-first; and 600 m free rifle, where he was placed forty first.
