Born in Moscow to a noble family, his father was a Russian Royal House Chamberlain. In 1899 graduated from Moscow Imperial University with a law degree; was conscripted by the army and served in a grenadier regiment. In 1902 enrolled at Moscow Theological Academy and by 1906 became [[archimandrite]] and rector of Tula seminary.
After the [[Bolshevik Revolution]] he was arrested several times and in 1922 exiled to Kazakhstan. In 1926 he returned to Leningrad and was appointed [[Archbishop]] of Khutyn, that is, the vicar of the Novgorodian [[diocese]]. He ran the diocese for much of the next seven years while [[Metropolitan]] [[Arsenius (Stadnitsky) of Novgorod|Arsenius (Stadnitsky)]] was in prison or exile. In 1933 Alexei was briefly Archbishop of [[Novgorod]] (for several months) and then [[Metropolitan]] of Leningrad.
On [[September 4]], 1943, Alexei I together with a delegation of senior Russian Orthodox clerics met with Joseph Stalin in the Kremlin where a historic decision was made regarding the fate of the Church in the state ruled by the militantly atheist Communist party. In the midst of World War II, Stalin decided to allow the Russian Orthodox Church to function after two decades of severe persecution. The Patriarchate of Moscow was re-established and many churches throughout the Soviet Union were re-opened. Stalin tried to appeal to patriotic feelings of the Russian people especially peasantry (the backbone of the Red Army), many of whom grew up in still deeply religious families.