From 1994 – 1996, Grinin was Director of the Fourth European Department at the Russian Ministry of Foreign Affairs, when he was appointed by Boris Yeltsin as Ambassador of Russia to Austria in 1996, and held the post in Vienna until 2000. After this posting he returned to Moscow, and was appointed by Vladimir Putin as Ambassador of Russia to Finland in 2003, and held this post until 2006, when he was appointed as Ambassador of Russia to Poland. Since July 2010 until 31.12.2017 Grinin served as Ambassador of Russia to Germany in Berlin.
After graduating from the Moscow State Institute of International Relations in 1971 he commenced diplomatic work, working at the Soviet Embassy in West Germany from 1973 – 1980. After his posting to West Germany he returned to Moscow and attended the Diplomatic Academy of the Ministry of Foreign Affairs of the USSR, graduating in 1982. From 1982 – 1986 he participated in Soviet – American negotiations on disarmament and arms control in Geneva. He was then posted to the Soviet Embassy in East Germany from 1986 – and then Germany from 1990 – 1992.