Adolphus FitzClarence was born at Bushy House. He attended a boarding school in Sunbury-on-Thames before being sent to sea at the age of eleven in 1813. He subsequently served as a midshipman aboard Newcastle based in North America and then later in the Mediterranean Sea. On receiving his commission as lieutenant in April 1821, he transferred to Euryalus and after being promoted to the rank of commander in May 1823, he later served aboard Brisk and Redwing in the North Sea. When promoted to captain in December 1824, he commanded Ariadne in 1826, Challenger in 1827 and Pallas in 1828.

On the accession of his father as king in 1830, he took command of the Royal Yacht, Royal George. His father also granted him and his siblings the rank of a younger son/daughter of a marquess by Royal Warrant of Precedence in 1831, enabling him to prefix Lord before his name and he was knighted the following year. He was also appointed Groom of the Robes in 1830 and a Lord of the Bedchamber in 1833. On the death of his father and the accession of his cousin Victoria in 1837, FitzClarence retained command of the Royal Yacht, until he was promoted to a rear-admiral in 1853 and his allowance allowed to continue. The queen reported that he "burst into tears, and said it was unexpected, for they (the FitzClarences) did not dare to hope for anything" In 1848, he also became a naval aide-de-camp to the queen and retained the office until he died, unmarried, at Newburgh Priory in 1856.