David Edward Malan attended the Boys' High School, Wellington, and passed the matriculation examination of the University of the Cape of Good Hope in 1906. Continuing his studies at Victoria College, Stellenbosch, he was awarded the Bachelor of Arts (BA) degree with honours in zoology by the university in 1910. Studying under Professor E.J. Goddard* he completed the Master of Arts (MA) degree in 1912. Goddard and Malan published the following papers at this time, presumably based on the latter's research for the MA degree: 'The South African Hirudinea' [leeches] (Part 1: Annals of the South African Museum, 1912, Vol. 11(4), 13 pp.; Part 2: Transactions of the Royal Society of South Africa, 1913, Vol. 3, pp. 249-255) and 'Contributions to a knowledge of South African Oligochaeta' [earth worms] (Transactions of the Royal Society of South Africa, 1913, Vol. 3, pp.231-248). They also read a paper at the annual congress of the South African Association for the Advancement of Science in 1912 on 'Some Antarctic fresh water annulates', but only the title was published in the society's Report for that year.
Malan subsequently proceeded to Zurich, Switzerland, where he was awarded a doctoral degree for a thesis titled Ergebnisse anatomischer untersuchung an Standfuss'schen Lepidopteren Bastarden (Results of anatomical investigation of [regional] Lepidoptera hybrids; 1917). Upon his return to South Africa he was employed at the Transvaal University College, Pretoria (later the University of Pretoria). In 1919 he became a foundation member of the South African Biological Society. He was a member also of the Royal Society of South Africa. Some years later he and D.J. Malan published a paper on 'The spermatogenesis of Locustana pardalina (Walker) (The Brown Locust)' in the Transactions of the Royal Society of South Africa (1926, Vol. 13, pp. 1-23). In 1933 he was a member of the Pretoria Entomological Club.