His great-grandfather was the Voortrekker leader, Gerrit Maritz, and his mother was a sister of General Christian Frederick Beyers.
He graduated in 1908 and earned a Rhodes Scholarship, which allowed him to further his studies at Trinity College, Oxford, where he obtained a Bachelor of Arts in 1912.
[1] Maritz qualified for the Middle Temple in November 1912 and began practising as an advocate in Pretoria I 1913.
As a result, Maritz, along with Tielman Roos and Oswald Pirow, formed an alternative Bar, the so-called Rebel-Bar.
[1] Maritz took silk in 1926 and in 1930 he was made judge of the Transvaal Provincial Division of the Supreme Court.