[1] By 1526 he had followed his father and siblings into royal service, although he does not seem to have shared the ambitions or abilities of his brothers, Edward and Thomas, and did not progress at court.
[10][11] In 1536 he appears to have replaced Mark Smeaton in the privy chamber[12] and following his sister's marriage, he was appointed to several offices chiefly related to the administration of her estates, some of which he lost at her death.
[13] In 1544 he was made captain of the ship Lyon of Hamburgh under the command of his brother Thomas, Lord High Admiral, but was held to be culpable when in November it foundered in the Dart estuary during a storm.
He was offered no further military or naval command following this incident, and some time in 1545, lost his position in the household of Katherine Parr.
[1] He is not mentioned in the diaries of Edward VI, although he received a number of royal grants of land during the reign of his nephew.
It seems Henry Seymour did not respond, and did well under the administration of his brother's replacement, John Dudley, 1st Duke of Northumberland.