On demobilisation after the Second World War, Macklin followed his early ambition and became a racing driver, although an early attempt to enter a race on the Isle of Man was refused on grounds that he had no experience.
Na desmobilización logo da segunda guerra mundial, Macklin seguiu a súa ambición inicial e converteuse nun piloto de carreiras, aínda que o primeiro intento de entrar nunha carreira na Illa de Man foi rexeitado debido a que non tiña experiencia.