Maclear entered the Navy in September 1851 as a cadet on board the frigate , then bearing the broad pennant of Commodore
Christopher Wyvill, then commanding the Cape station. In her he saw service during the
Xhosa Wars in 1851, and afterwards, as a
midshipman of , served in the
Baltic and in the
Black Sea from 1854 to 1856, receiving, the Baltic, Turkish, and Crimean medals, with the clasp for
Sevastopol. He passed his
lieutenant's examination in July 1857, and served on board in the
Red Sea as mate during the outbreak at
Jeddah in 1858. On 19 May 1859 he was promoted to lieutenant, and shortly afterwards was appointed to
HMS Sphinx, in which he served on the
China station until 1862, being present at several engagements during the second Chinese war, and especially at
Taku Forts, for which he received the clasp. In 1863 he went to to qualify as a gunnery lieutenant. In February 1864, Maclear was appointed to ,
flagship on the China station. He returned to England in her and, in October 1867, was chosen to be
first lieutenant of the frigate
HMS Octavia, flagship of Commodore Heath in the
East Indies. In her he took part in the
Abyssinian campaign of 1868, earning the medal and his promotion to
commander on 14 August 1868. In 1872
Challenger was commissioned by Sir George Nares, with Maclear as his commander, for the voyage of scientific discovery around the world. Returning home in her in 1876, on 14 August Maclear was promoted to
captain. In 1879 he succeeded Sir George Nares in command of the sloop and remained in her until 1882, completing the survey of the
Straits of Magellan. From 1883 to 1887 he commanded on surveying service. On 20 June 1891 he reached
flag rank, and two months later retired. He was promoted to
vice admiral on the retired list in 1897, and to
admiral on the retired list on 21 January 1903. After leaving the sea, Maclear assisted in the compilation of several volumes of the official sailing directions, especially those for the Eastern Archipelago (1890 and 1893), for the west coasts of Central America and the United States (1896), for Bering Sea and Alaska (1898), and the 'Arctic Pilot' (vol. ii. 1901 and vol. iii. 1905). He was a fellow of both the
Royal Geographical Society and
Royal Meteorological Society. ==Family==