Jonsson makes his third Paralympics and had hoped to improve his sixth place from Rio de Janeiro.
But the former WC and EC runner-up 6.50 was just over half a meter from a bronze.
With that result, he was 25 centimeters ahead of the future name Olof Ryberg, who three weeks ago got the chance to make his Paralympic debut after Per Jonsson was injured.
Iran's Amir Khosravani took gold with a jump of 7.21.