ship's captain, was born in Whitehead, Co Antrim, on 3 March 1908, the son of Captain George Allen Johnston and his wife Isobella, née Downey. He was educated at Whitehead School and left at 16 to go to sea as an apprentice with the Head Line. He qualified point by point until in 1933 he passed out as a master mariner.

In 1936 he took up an appointment with the Falklands Islands Company as chief officer of their vessel the SS Lafonia, subsequently becoming master. In 1940 the ship was requisitioned by the Admiralty and Johnston joined the Royal Navy. He served as a lieutenant in command of rescue tugs and took part in a number of engagements in the Mediterranean, including the landings in southern Europe. In 1946 he returned to the Falkland Islands to take command of a new Lafonia. When this vessel was sold in 1949, Governor CLIFFORD persuaded Johnston to join the Falkland Islands Dependencies Survey as master of the first John Biscoe. When the new John Biscoe was commissioned, Johnston as senior master was given command and he served in her until his retirement through ill health in 1965.

Calm and completely unruffled at all times, he was ideally suited by temperament to command an Antarctic survey vessel. Stuck in ice for days on end was no frustration to him: he would merely look over the bridge, decide that nothing could be done and go back to his book. A great reader at sea, Johnston was also a very skilled bridge player, but his greatest enjoyment was undoubtedly a flutter on roulette, cribbage, the dogs or the horses. After some years when his legs became extremely painful, he died on 27 February 1968 in Larne, Co Antrim.

A man of considerable stature with a tremendous sense of humour, he was much liked and respected by all who knew him. He was awarded the Polar Medal in 1963.