At the outbreak of World War I Lawrence was a university post-graduate researcher who had for years travelled extensively within the Ottoman Empire provinces of the Levant (Transjordan and Palestine) and Mesopotamia (Syria and Iraq) under his own name. As such he became known to the Turkish Interior Ministry authorities and their German technical advisors. Lawrence came into contact with the Ottoman–German technical advisers, travelling over the German-designed, -built, and -financed railways during the course of his researches.
Even if Lawrence had not volunteered, the British would probably have recruited him for his first-hand knowledge of Syria, the Levant, and Mesopotamia. He was eventually posted to Cairo on the Intelligence Staff of the GOC Middle East.
Contrary to later myth, it was neither Lawrence nor the Army that conceived a campaign of internal insurgency against the Ottoman Empire in the Middle East, but rather the Arab Bureau of Britain's Foreign Office. The Arab Bureau had long felt it likely that a campaign instigated and financed by outside powers, supporting the breakaway-minded tribes and regional challengers to the Turkish government's centralised rule of their empire, would pay great dividends in the diversion of effort that would be needed to meet such a challenge. The Arab Bureau had recognised the strategic value of what is today called the "asymmetry" of such conflict. The Ottoman authorities would have to devote from a hundred to a thousand times the resources to contain the threat of such an internal rebellion compared to the Allies' cost of sponsoring it.
At that point in the Foreign Office's thinking they were not considering the region as candidate territories for incorporation in the British Empire, but only as an extension of the range of British Imperial influence, and the weakening and destruction of a German ally, the Ottoman Empire.
During the war, Lawrence fought with Arab irregular troops under the command of Emir Faisal, a son of Sherif Hussein of Mecca, in extended guerrilla operations against the armed forces of the Ottoman Empire. He persuaded the Arabs not to make a frontal assault on the Ottoman stronghold in Medina but allowed the Turkish army to tie up troops in the city garrison. The Arabs were then free to direct most of their attention to the Turks' weak point, the Hejaz railway that supplied the garrison. This vastly expanded the battlefield and tied up even more Ottoman troops, who were then forced to protect the railway and repair the constant damage.