He was the son of Alexandru Iliaș, Prince of Wallachia between 1616–1618 and 1627–1629.
He became Prince when the Ottoman Sublime Porte deposed his predecessor Leon Tomșa.
[1] However, he did not manage to occupy the throne, because Matei Basarab, occupied the throne with the help of George I Rákóczi, Prince of Transylvania and also with the support of the Pasha of Silistra.
[1][2] Radu Iliaș tried to take back his throne, but in the Battle of Plumbuita Monastery on October 20/30, 1632, his forces were defeated.
Following negotiations with the Porte, Matei Basarab received the title and the investiture flag and became the next Prince of Wallachia.