It was his habit of successfully waging war without any casualties that made him a hero and a legend on both sides.
He was married twice, firstly to Petra (née Schultz) with whom he had a daughter, Inge-Maria, born in 1913, and secondly to Ingeborg (née Engeström).
Luckner was also an accomplished magician – Kaiser Wilhelm was fascinated by his tricks and frequently invited Luckner aboard his yacht to entertain important dignitaries.
At the beginning of the First World War, Germany converted a considerable number of merchant ships into merchant raiders by equipping them with guns and sending them in search of Allied merchant shipping. Most of the armed raiders were not particularly successful, but they did tie up considerable Allied forces in hunting them. By early 1915, most of the armed raiders had either been hunted down and sunk or had run out of fuel and been interned in neutral ports.
Hoping to revive commerce raiding, the Imperial Navy equipped the impounded three-masted sailing ship Pass of Balmaha (1571 tons) with two 105 mm guns hidden behind hinged gunwales, several machine guns, and two carefully hidden 500 HP auxiliary engines. She was commissioned as the auxiliary cruiser Seeadler (Sea Eagle). As virtually the only officer in the German Navy with extensive experience of large sailing ships, Luckner was appointed her commander.
On 9 January 1917, Seeadler came upon a single-funneled steamer. She raised a signal requesting a time signal (not an uncommon thing for a sailing ship long out of contact with land to do), and too late for evasive action, raised the German ensign. Three shots were needed to persuade the 3,268 ton Gladys Royle, carrying coal from Cardiff to Buenos Aires, to stop. Her crew was taken off unharmed, and she was scuttled.
On 10 January 1917, Seeadler encountered another steamship, which refused to identify itself. The German ensign was raised and a shot fired across the bow of the Lundy Island, carrying sugar from Madagascar. The steamer still refused to stop, and four shots were fired directly at her. The steamer hove to and lowered its boats, but its captain ignored an order to come to Seeadler. A German boarding party was sent over and discovered that the crew had abandoned ship when the first shots were fired, leaving the captain alone. Later, Captain Bannister told Luckner that he had previously been captured by a German raider, and had given his parole which he had broken; thus he was not anxious to be a prisoner of war again. Luckner continued his voyage southwards, and by 21 January, he was in mid-Atlantic between Brazil and West Africa when he found the 2,199 ton French three-masted barque Charles Gounod, loaded with corn. Charles Gounod was quickly dispatched, but her log book recorded information about other ships she had met and their intended route.
On 24 January, the small 364-ton Canadian schooner Perce was met and sunk by machine gun fire, after taking off the crew and the captain's new bride. The 3,071 ton French four-masted Antonin, loaded with Chilean saltpetre, was overhauled on 3 February and soon scuttled. On 9 February, the 1,811 ton Italian Buenos Ayres, also carrying saltpetre, was sunk. On 19 February, a four-masted barque was spotted, which immediately piled on sail in an effort to get away; however, Seeadlers engines allowed her to overhaul the 2,431 ton British grain-carrying Pinmore. By coincidence, von Luckner had sailed on Pinmore in his civilian sailing days, back in 1902. Luckner took Pinmore into Rio de Janeiro in order to get more supplies, before eventually scuttling her.
The next ship to be stopped was the Danish barque Viking, but as there was nothing unusual about its cargo the neutral ship was allowed to proceed unmolested.
On the morning of 26 February, the 1,953 ton British barque British Yeoman, carrying a welcome cargo including chickens and pigs, was stopped and sunk, and the same evening the French four-master Le Rochfoucauld fell victim to the Seeadler. The boarding party discovered that Le Rochfoucauld had only recently been stopped by a British cruiser which was looking for Seeadler.
On the evening of 5 March, Seeadler discovered a four-masted barque in the moonlight and signalled "Stop immediately! German Cruiser". Bizarrely, the captain of the 2,206 ton French ship Dupleix rowed across to Seeadler, convinced that another French captain was playing a practical joke on him. He was soon disabused of the idea when his ship was scuttled. Seeadlers next victim on 10 March was asked for the time, but ignored the signal. Luckner ordered a smoke generator to be lit, and the 3,609 ton Horngarth turned back to render assistance to the 'burning' sailing ship. A single shot put the British ship's radio out of commission, and this resulted in the only loss of life in the Seeadler 's voyage. A British sailor, Douglas Page, was unfortunately killed by a steam pipe ruptured by the shot. Horngarth was soon scuttled by Seeadlers now experienced crew.
By this time, Luckner had the problem of feeding and keeping safe nearly 300 prisoners, in addition to his own crew. Consequently, when on 20 March, the French four-masted barque Cambronne was captured, Luckner arranged for the ship's top gallant mast and additional spars and sails to be removed, before putting his prisoners aboard Cambronne under the command of Captain Mullen of Pinmore. The much-reduced rigging on Cambronne ensured that Seeadler would be able to make good its escape before its location could be reported to the hunting ships.
The Royal Navy was well aware of Seeadler's general location and set a trap consisting of the armed merchant cruiser Otranto and the armored cruisers Lancaster and Orbita(?) at Cape Horn. However, a severe storm blew Seeadler considerably further south, before she entered the Pacific Ocean on 18 April and sailed north along the Chilean coast. By early June, Seeadler was east of Christmas Island and learned that the United States had entered the war. Seeadler turned her attention to American shipping, sinking the 529 ton A B Johnson of San Francisco on 14 June, the 673 ton R C Slade the next day, and the schooner Manila on 8 July. By this time, Seeadler needed to be laid up so that her hull could be scraped clean. She put into the small island of Mopelia, a coral atoll some 10 km in diameter in the Society Islands, some 450 km from Tahiti.
The crew and their 46 prisoners were now stranded on Mopelia, but they managed to salvage provisions, firearms, and two of the ships' boats.
Three days after leaving Mopelia, they reached Aitu Island in the Cook Islands group, where they pretended to be Dutch-American seamen crossing the Pacific for a bet. The New Zealand Resident, the administrator of the island, gave them enough supplies to reach another island in the group, Aitutaki, where they posed as Norwegians. The New Zealand Resident in Aitutaki was suspicious, but had no means of detaining the group, and von Luckner quickly took his party to the island of Rarotonga. Approaching Rarotonga in the dark, Luckner saw a dark ship which he thought was an auxiliary cruiser, but in fact was a beached ship. Luckner pressed on to the Fijian island of Wakaya, arriving after a voyage of 3,700 km in an open boat. Most people on Wakaya accepted their story of being shipwrecked Norwegians, but one sceptic called a party of police from the old Fijian capital of Levuka. On 21 September, the police bluffed that the non-existent gun on the inter-island ferry Amra would blow Luckner out of the water. Not wishing to cause bloodshed, and not realizing that the police were unarmed, Luckner and his party surrendered and were confined in a prisoner-of-war camp on Motuihe Island, off Auckland, New Zealand.
Meanwhile, back on Mopelia, a small French trading ship Lutece anchored outside the reef. Leutnant Kling of Seeadler, having heard of his captain's capture on the radio, sailed out to Lutece and captured it at gunpoint. The French crew was put ashore with the other prisoners, and all the Germans embarked on the ship, now renamed Fortuna, and set course for South America. The master of A B Johnson, Captain Smith, then took the remaining open boat from Mopelia with three other American seamen, and sailed 1,600 km to Pago Pago, arriving on 4 October, where they were finally able to inform the authorities of the activities of Seeadler and arrange for the rescue of the other 44 sailors still stranded on Mopelia.
The Fortuna, meanwhile, came to grief when she struck uncharted rocks off Easter Island. The crew scrambled ashore, where they were interned by the Chileans for the remainder of the war.
In 1926 he raised funds to buy a sailing ship which he called Vaterland and set out on a goodwill mission around the world leaving Bremen on September 19 and arriving in New York on October 22, 1926. An entertaining speaker, he was widely admired for his seamanship and for having fought his war with minimal loss of life. This opened him many doors in the United States where he spoke on hundreds of occasions across the country, both in German and, later, increasingly English. He won the support of many notables, diplomats, politicians and even the American Legion. Henry Ford presented him with a motor car and the city of San Francisco made him an honorary citizen. President Coolidge wanted to meet him but Luckner declined at the request of his government. Feeling that his goodwill mission as he calls it in his travelogue Sea-devil conquers America could neither have greater success elsewhere nor could be financially sustained by the income as speaker however popular and successful he returned to Germany where he arrived on April 19, 1928.
He was a frequent visitor to the Heydrich home in Halle where he inspired a young Reinhard Heydrich, with stories of his adventures on Seeadler, to join the inter-war Reichsmarine. In 1937 and 1938, he and his wife undertook a round-the-world voyage in his yacht Seeteufel, being welcomed in New Zealand and Australia, though some viewed him as an apologist for the Nazi regime.
During the Second World War, Hitler tried to use him for propaganda purposes, though, as a Mason, he was not in one of the Nazi's favoured groups of people. Luckner refused to renounce his membership of the Masons or the various honorary citizenships granted in the US, and consequently he suffered by having his bank account frozen. In 1943, he saved the life of a Jewish woman, Rose Janson, whom he provided with a passport he found on a bombsite, and who subsequently managed to escape to the US via a neutral country. At the end of the war, the mayor of Halle, where he was living, asked him to negotiate the town's surrender to the approaching American forces, which he did, though he did not return to the town after hearing that the Nazis had condemned him to death.
Luckner was extremely strong and was noted for his ability to bend coins between his thumb, index and middle finger of his right hand and to tear up telephone directories (the thickest being that of New York) with his bare hands. On the occasion of his visit to Australia in 1938, the Sydney Labour Daily published a cartoon showing Kaiser Wilhelm tearing up the Belgian Neutrality Pact, Adolf Hitler tearing up another agreement, and Luckner tearing up a directory, with the caption "They All Have The Habit".
After the Second World War, Luckner moved to Sweden, where he lived in Malmö with his Swedish second wife Ingeborg Engeström, until his death in Malmö at the age of 84 in 1966. He is buried in Main Cemetery Ohlsdorf, Hamburg.