Ernst Lehmann was born in 1886 in Ludwigshafen am Rhein. At the age of 14, he decided that he wanted to build ships. He studied engineering at Berlin-Charlottenburg College and received his degree in 1912. By this time, he had already joined the navy and had attained the rank of naval reserve lieutenant.
Upon graduation, he began work at the Imperial Dockyards in Kiel. He did not find this work satisfying so, encouraged by Dr. Hugo Eckener, he joined the DELAG to serve as pilot of the passenger airship LZ 17 Sachsen. He commanded a total of 550 flights of this ship.
During the First World War, Captain Lehmann commanded army airships, beginning with the Sachsen and followed by the LZ XII, LZ 90, LZ 98, and LZ 120.
After the war, Captain Lehmann continued his involvement with the airships, now used for civilian purposes. He made preparations to fly the naval airship L 72 on the first transatlantic crossing of an airship in 1919. Permission was denied by the German government. In 1920, he spent six months in Sweden studying the economics of an airship line between Stockholm and the Mediterranean, with a stopover in Friedrichshafen. These plans were never realized.
With the founding of the Goodyear Zeppelin Corporation in 1923, Captain Lehmann served as Vice President in charge of engineering.
In 1924, Captain Lehmann was second-in-command of LZ 126 on the first nonstop transatlantic flight between the European and American mainlands. The purpose of the flight was to deliver the Zeppelin to its new owners, the United States Navy, who rechristened the ship USS Los Angeles.
Captain Lehmann served as commanding officer on more than 100 of the flights of the Graf Zeppelin between 1928 and 1936. In 1936, he commanded 10 round-trip flights to Lakehurst on the new Hindenburg.
Although Max Pruss was the commanding officer of the last flight of the Hindenburg, Captain Lehmann was the most senior officer on board. He was fatally burned when the ship caught fire at Lakehurst on May 6, 1937; he died the following day.