 Johnston's next international assignment was the 1949 – 50 tour to South Africa. The tour started badly; after taking a total of 5 / 28 in an innings win over Zululand in a non-first-class match, he fell asleep at the wheel outside Durban following a team function. He missed a turn, skidded across gravel and flipped and crashed his car. After a few hours, medical help arrived and Johnston was hospitalised. The team manager Chappie Dwyer was mistakenly informed that Johnston had died, and the bowler later described his injury as a "nine-iron divot in the top of my skull". Johnston started coughing up blood, and he and Dwyer sought to have the accident private. However, news was leaked back to Australia, and Johnston's mother fainted; her husband and other son had already died and she was fearful that her lone remaining relative had joined them. After complaining of chest pain, it was later discovered that Johnston had two broken ribs and he had to rest further.
