Buller was educated at Cambridge, and then at the Middle Temple, where he and his cousin Thomas Wise* were bound with Alexander and John Maynard†, associates of his father, Sir Richard.
Thanks to his father’s dominant local position, Buller was elected for Saltash both in 1624 (when he was barely of age) and 1625, on the latter occasion as Sir Richard’s junior partner. However, he played no recorded part in either parliament. In 1628 Sir Richard’s influence over Saltash was challenged, and Buller instead sought election at Mitchell. He probably approached the borough’s principal patron, John Arundell* of Trerice, his father’s political ally, perhaps also anticipating local support from his relatives, the Vivians of St. Columb Major.
During the 1630s Buller began to play a minor role in Cornish local government. In 1636 he inherited property in Montgomeryshire from his uncle Sir John Hayward*, and was apparently shortlisted as sheriff of that county in both 1638 and 1639. His lands were assessed for subsidy in 1641 at £10.
