He was knighted by Henry FitzAlan, 19th Earl of Arundel, on 2 October 1553, and elected to parliament as member for Maldon in 1555 and Chichester in 1559.
He sat in the Irish House of Commons as member for Carlingford in 1559, and two years later was nominated lieutenant of Leix and Offaly.
He managed to keep the district quiet, but in 1564, when commissioners were sent from England to report on the condition of the Irish government, charges of corruption in dealing with funds appointed for the payment of the soldiers were brought against Radclyffe.
for Hampshire, he received the office of warden and captain of the town, castle, and isle of Portsmouth, and he was active in that capacity until his death.
[1] For the next decade, until his death, he was the patron of The Earl of Sussex's Men, who performed several of the early Shakespeare plays at The Rose (theatre) under Philip Henslowe, including Titus Andronicus and Richard III.
Henry and Honora had two children: a son Robert Radclyffe, 5th Earl of Sussex (12 June 1573 – 22 September 1629), first married to Bridget Morrison, from his second marriage to Frances Shute Meautys, a daughter Jane Radcliffe.