He joined the British Army in 1938 and was commissioned into the Queen's Royal Regiment. He was with the 2nd Battalion of this regiment in Palestine and the Western Desert from 1939 to July 1941 when he joined the Long Range Desert Group (LRDG).
He took part in a number of operations, including the SAS raid on Tobruk in August/September 1942, which earned him the Military Cross. He was wounded in an air raid on the LRDG base at Kufra in October 1942 and nearly lost an arm. He rejoined the LRDG in February 1943, when they underwent training in Lebanon before being sent to the Aegean.
He took command of the LRDG at the end of 1943 after the death of his predecessor Jake Easonsmith during the Battle of Leros. He based himself at Bari in southern Italy from which he mounted a successful raid on Corfu and staged operations in the Dalmatian islands and Yugoslavia. In September 1944, he was parachuted into Albania at night. Shortly after landing he fell 30 ft into a ravine and severely damaged his spine.
Despite being in continual pain, Lloyd Owen directed special forces operations in the mountains for the next three months. Eventually Lloyd Owen was evacuated to Italy, was successfully operated on, and told not to return to his former activities. But he managed to bluff his way past a medical board and returned to Albania, although this time by boat. The LRDG was eventually disbanded in June 1945. For his leadership in the Balkans, Lloyd Owen was awarded the DSO that year.
After the war, he had various appointments in Britain, including a period on the staff at Sandhurst. In 1952, he was appointed Military Assistant to the High Commissioner in Malaya. He then commanded the 1st Battalion of the Queen's Royal Regiment from 1957 to 1959. In the early 1960s he led 24 Infantry Brigade Group in Kenya and was then, from 1966 to 1968, GOC, Cyprus District. From 1968 to 1969 he was GOC, Near East Land Forces and, from 1969 to 1972, president of the Regular Commissions Board. He was appointed OBE in 1954 and CB in 1971.
He wrote several book about his experiences - The Desert My Dwelling Place published by Cassell in 1957 and again by Panther Books the following year, and more recently Long Range Desert Group 1940-1945: Providence Their Guide, published by Leo Cooper/Pen & Sword Books in 2001.