Stalin was a leader in the Russian (Soviet) Government late in World War I:
"Stalin became part of an informal foursome leading the government, alongside Lenin, Trotsky, and Sverdlov;[183] of these, Sverdlov was regularly absent, and died in March 1919.[184] Stalin's office was based near to Lenin's in the Smolny Institute,[185] and he and Trotsky were the only individuals allowed access to Lenin's study without an appointment." ... Stalin was appointed the People's Commissar for Nationalities. [ date? ]
Although the rest of the Allies hastily invaded Russia in an attempt to overthrow the Bolsheviks--perhaps a bit of a side war to WWI, akin to the Russian invasions of Finland.
The Germans agreed to let the Russians negotiate a peace treaty. Lenin, leader of the Russian revolution, sent Trotsky, his second in command, to the Polish town of Brest-Litovsk to make the negotiations. Trotsky refused the terms of the treaty initially, but had to sign in March 1918 when the German army responded to his delaying tactics by resuming an invasion of Russia. [ source : https://classroom.synonym.com/significance-russian-withdrawa... ]
"Stalin became part of an informal foursome leading the government, alongside Lenin, Trotsky, and Sverdlov;[183] of these, Sverdlov was regularly absent, and died in March 1919.[184] Stalin's office was based near to Lenin's in the Smolny Institute,[185] and he and Trotsky were the only individuals allowed access to Lenin's study without an appointment." ... Stalin was appointed the People's Commissar for Nationalities. [ date? ]
[ from https://en.wikipedia.org/wiki/Joseph_Stalin#Consolidating_po... ]
Franklin Roosevelt also held a relatively high office: Assistant Secretary of the Navy.