In 1683 he was appointed first Commissioner of the Victualling Office, a post he held until 1690. He entered politics in 1678, being elected to represent Aldeburgh. He became the representative for New Shoreham in 1685, and just before the accession of King William III he again became Controller of the Navy on 12 October 1688, a post he held until his death on 29 January 1714. He was appointed joint Commander-in-Chief of the fleet sent to Ireland in 1690, alongside Vice Admiral Henry Killigrew and Sir John Ashby. They commanded the fleet from the third rate . They remained in command until the winter when the fleet returned to Britain. They resigned their commissions and were replaced by Admiral Edward Russell. Haddock went into retirement from active service, dying in London on 26 January 1715. He was buried on 6 February in the churchyard of St Clement's Church, Leigh-on-Sea.