In 1937 Johnson successfully contested a special election for Texas's 10th congressional district, which covered Austin and the surrounding hill country. He ran on a New Deal platform and was effectively aided by his wife. He served in the House from April 10, 1937 to January 3, 1949.
President Roosevelt found Johnson to be a welcome ally and conduit for information, particularly with regard to issues concerning internal politics in Texas (Operation Texas) and the machinations of Vice President Garner and Speaker of the House Sam Rayburn. Johnson was immediately appointed to the Naval Affairs Committee. He worked for rural electrification and other improvements for his district. Johnson steered the projects towards contractors that he personally knew, such as the Brown Brothers, Herman and George, who would finance much of Johnson's future career. In 1941, he ran for the U.S. Senate in a special election against the sitting Governor of Texas, radio personality W. Lee "Pappy" O'Daniel in an election marked by massive fraud on the part of both campaigns.Johnson was not expected to win against the popular governor, but he ran a strong race and was declared the winner in unofficial returns — ultimately losing due to controversial official returns.
After America entered the war in December 1941, Johnson, still in Congress, became a commissioned officer in the Naval Reserve, then asked Undersecretary of the Navy James Forrestal for a combat assignment. Instead he was sent to inspect the shipyard facilities in Texas and on the West Coast. In the spring of 1942, President Roosevelt needed his own reports on what conditions were like in the Southwest Pacific. Roosevelt felt information that flowed up the military chain of command needed to be supplemented by a highly trusted political aide. From a suggestion by Forrestal, President Roosevelt assigned Johnson to a three-man survey team of the Southwest Pacific.
Johnson reported to General Douglas MacArthur...