After the Bolshevik revolution in October, he led the Soviet delegation to the peace talks with Germany in Brest-Litovsk, but was soon replaced by Trotsky, since Joffe favored continuing the war.
In April 1918 Joffe was appointed Soviet ambassador in Berlin, at which time he worked with German Socialists and revolutionaries to prepare for revolution in that country. He later admitted that his efforts “accomplished little or nothing of permanent value, for we were too weak to provoke a revolution.” He was expelled from Germany in November 1918. In 1920 he led the Russian delegation to the peace talks with Poland.
In late 1922 he traveled to the Far East to strengthen Soviet influence in that region of the world. In China he sought to assure the nationalists that the Bolsheviks were not interested in promoting Chinese communism, something of which Moscow was ashamed in later years.
Joffe continued to be closely allied to Trotsky, and was part of the opposition to Stalin and the ruling triumvirate after Lenin’s death. He was ambassador in Vienna (1923-1924) and Tokyo (1924-1925). By early 1927 he was gravely ill, but was refused permission to travel abroad for medical treatment — even at his own expense. Stalin subjected him to increasing harassment, and he shot himself in the Kremlin as a protest against the expulsion of Trotsky and Zinoviev from the party.
Joffe’s funeral was attended by thousands, even though it had not been announced, and was Trotsky’s last public appearance in Russia.
His farewell letter to Trotsky is unique as a human and political document and a statement of revolutionary morality: “All my life I have been convinced that the revolutionary politician should know when to make his exit and that he should make it in time... when he becomes aware that he can no longer be useful to the cause he has served.... Human life has sense only in so far as it is spent in the service of the infinite — and for us mankind is the infinite.” He went on to say that perhaps his suicide would help arouse the party to the condition it had reached, one in which it was unable to react in any way to the “monstrosity” of Trotsky’s expulsion from it.