Son of Frederick Petrus Willem and Anna Maria Petronella de Swardt. Husband of Mrs. Janetta Louisa Francina Coetzer
LG Sup 31 July 1945 pg. 3926 - "This officer has displayed the highest standard of efficiency and courage. He has completed a very large number of sorties including many reconnaissances. In April 1945, Lieutenant de Jongh was leading a formation of a strafing reconnaissance. A convoy of motor transport was observed in the Montebelluno area. Despite adverse weather and heavy enemy opposition, this officer led the formation into attack. Twelve of the enemy vehicles were subsequently destroyed and a further three damaged. In air fighting Lieutenant de Jongh has been responsible for the destruction of at least one enemy fighter and has damaged others."