Oliver St. John began his career in the household of Prince Edward, and on the accession of his master he entered the royal household. His own court connexion combined with his father’s influence explain his return as one of the knights for Bedfordshire to the first Parliament of the reign, although as yet he had no experience of local affairs. The designation ‘junior’ on the election indenture leaves no doubt that it was he and not his uncle and namesake who was then returned. All that is known of his part in the Commons is that on 21 Feb. 1549 he was licensed to be absent for three days, presumably on account of problems arising from his wife’s succession to the Fisher inheritance in the midlands. If he was re-elected to the King’s second Parliament, it was not for Bedfordshire, but he could have obtained a seat for almost any borough. From 1550 he figured increasingly in county administration and from 1554 he served as a magistrate.3CJ, i. 8.
Ennobled shortly after his father’s death St. John demonstrated his allegiance to Elizabeth in both public and private matters. His second marriage to a widow well provided for by two of her three previous husbands further enriched him. He made his will on 20 Apr. 1582 and died the following day.4APC, iv. v, vii, x, xiii; CPR, 1558-60, p. 74; 1563-6, pp. 43, 361; PCC 5 Bucke, 19 Mellershe, 32 Holney; HMC Var. iii. 87-88; Selden Soc. xii, 64 seq.; St.Ch.3/3/22, 7/34; C142/198/1; PCC 22 Tirwhite.