On his twenty-second birthday, (15.4.1944) John was married to Marion Craig Smaling, by Rev. Pearson at St. Martin's-in-the-Veld, Rosebank. Marion was the daughter of Bertram and Wilhelmena Smaling, her father being the mine manager of Witwatersrand Deep mine at Knights, which lay between Germiston and Pretoria. In February, 1945, they went to live at 79, First Avenue East, Parktown North, Johannesburg but three years later they moved to a double storied home in a newer suburb; No: 8, North Road, Dunkeld West. Their two daughters were born prior to this move Jillian Leslie Freemantle in 1945 and Anne Terry Freemantle in 1947.
John started work as an office boy at Max Pollak & Freemantle on 18th April, 1940 and, after his war service and military discharge, was re-employed as a Floor Dealer on the Johannesburg Stock Exchange. Some years later he became Office Manager and the chief Executive of the firm. However, during the years 1951 and 1952 he broke from the firm and became Chairman of a Civil Engineering Constructive Company. He was also a family man and spent most of his leisure hours with his daughters while doing his best to improve his home and garden, turning his hands to such projects as building a Wendy house in the garden for the girls, which the local council would not accept as they deemed it to be large enough to comprise a building suitable for occupation by adults and in need of building approval by them, so they insisted that he dismantle all his hard work.
John was involved in one particularly unfortunate incident when, apparently, a black man came to the door of their home demanding money and an altercation developed between this man, who became threatening, and Marion. John came to her defence, bringing his gun with him. When John ordered him to leave, the man lunged at him with a knife, knocking the gun from his hand. It went off and killed the assailant. Because this man was not legally considered an intruder into their home, as he fell at the threshold of the entrance, the police had to prosecute and this was a very stressful time for all the family, while awaiting the verdict of accidental death.