Marthin was born in Witbank on 19 February 1991 where he lived until the age of 5. His family then moved to Senekal in the Free State where he attended school from Grade 1 to Grade 12. In 2009 he matriculated at Paul Erasmus High School.

He obtained his LLB degree at North-West University, Potchefstroom Campus (Pukke) after which he did his clerkship at Human Le Roux & Meyerowitz in Bethlehem and then practiced for a year at the same firm.

In 2017 he and his wife moved to Worcester where he was appointed as Attorney at Muller Terblanche & Beyers. In 2022 he was appointed as Director and head of the collections department. 

For Marthin, the most important aspects are quality service and client satisfaction. Marthin also enjoys spending time with his family, and camping.