Warren took command of in 1808 and served in the Baltic Sea, carrying out operations against Russian shipping. He then commanded a frigate, in which he was charged with transporting Lucien Bonaparte and his family to England. He then sailed to the East Indies and played an important role in the Invasion of Java in 1811. He was made a Companion of the Bath at the end of the Napoleonic Wars in 1815, and commanded several more ships, including the royal yacht. He also held a number of shore appointments, being knighted and made a Knight Commander of the Royal Guelphic Order in 1835. Promoted to rear-admiral in 1837, he was made a Knight Commander of the Bath shortly before his death in 1839.