From 1951 he served as officer at the South African Navy, where he played a major role (with many others) to assist in making it become more bilingual.
He was member of the executive board of Vriende van Afrikaans, the Helderbergse Kultuurraad and other organisations.
Gideon Joubert was married, had four sons and lived in Heldervue, Somerset West.
Gideon founded one of the oldest and most well established wine circles in South Africa, the Heerengracht Wynkring.
Unlike other Christian non-fiction works about cosmology and cosmogony, Die Groot Gedagte does not do away with the Big Bang theory, but rather suggests that the Big Bang was the result of a greater Intelligence which had planned how the universe would turn out.