Johnson was born in the family row house located at 1st and East Capitol Streets (now a part of the location of the United States Supreme Court) in Washington, DC. He spent part of his early life in Newkirk, Oklahoma and then Kildare, Oklahoma. He then returned to Washington, DC, to complete his schooling at Sidwell Friends School, near 8th Street and I Street NW. He then went to George Washington University and pledged to the Delta Tau Delta fraternity. In his freshman year, he decided to take the Foreign Service Examination, claiming his residency as Oklahoma. Successful, he received an appointment to the Foreign Service of the United States, as appointments were made based on one's home state.
He spent his entire adult life in the service of his government. Johnson specialized in China and the rest of the Far East, first as a student interpreter, then as consular officer, Chief of the Division of Far Eastern Affairs, next as Assistant Secretary of State, and then as Minister and Ambassador on assignments to China before World War II. He served as minister to Australia during World War II (1941-1945).
Johnson first became intimately involved in shaping American policy toward China in 1925 when he assumed the office of Chief of the Division of Far Eastern Affairs in the State Department. From 1928 to May 1941, he was assigned to China as Minister Plenipotentiary and then as Ambassador Extraordinary and Minister Plenipotentiary. During those years, he contributed heavily to determining the conduct of US relations with China, which were based primarily on his personal papers in the Library of Congress and published and unpublished State Department records from 1925 to 1941 that emphasized his ideas and suggestions regarding American policy on China.
Johnson made major contributions during the Coolidge, Hoover, and the early Roosevelt administrations. He favored going as far as American interests would allow in helping China regain its sovereignty, and he consistently guided US Secretaries of State Kellogg and Stimson on a moderate course in their policy.
Under Kellogg, Johnson continually opposed interference in the civil war in China. He opposed joining the British at Canton and Hankow in punitive measures against Chinese strikers and other nationalists. He opposed harsh or recriminatory action against China during the Nanking Incident of 1927. He advocated conciliation in answering China's note of June 1925 requesting treaty revision. He suggested going as far as possible, unilaterally if necessary, in writing a new tariff treaty, and he favored gradual relinquishment of extraterritoriality.
Under Stimson, Johnson made a significant contribution when, as American Minister in China, he influenced Stimson's policy during the Shanghai affair. His advice for the United States to make a statement for upholding the terms of the Nine-Power Treaty was chiefly responsible for Stimson's letter of February 1932 to US Senator William E. Borah.
In the mid-1930s, Johnson's influence continued, but other officials gained ascendancy as policy became more oriented to Japan. He grew increasingly impatient with Japanese aggression and began suggesting a reappraisal of American policy toward Japan. While not yet recommending that the US assume any responsibility for the Chinese, he still advocated rearmament and reconsideration of its intention to grant independence to the Philippines.
By the end of the decade, Johnson openly advocated material support for China. The Chinese had then established a measure of order and had demonstrated a will to resist Japan and he believed they deserved support. His descriptions of the events of the war and of the valiant fight of the Chinese were instrumental in the decision to grant assistance to them.
Johnson married Jane Augusta Washington Thornton Beck in Peking (now Beijing), China. The second daughter of Wyoming pioneer George T. Beck, she was born on October 21, 1900, in Cody, Wyoming. She died February 28, 1991, in Washington, DC. at 91.
They were married in Peking and were then registered at the US consulate in Tientsin (now Tianjin), China, on October 10, 1931.