Sergey Grankin started playing Volleyball at 7. When he was 14, he received an invitation from "Neftyanik" (Yaroslavl), where he performed as a setter for the first time. Only 17, Grankin began performing in the Super League. Under the training of Sergei Shlyapnikov, head coach of "Neftyanik" and the Youth team of Russia, his skills and leadership qualities developed quickly enough.
Sergei Grankin captained the Youth team of Russia at the victorious European Championships in 2004 in Croatia, and the 2005 World Championships in India, where he first declared himself really loud. Largely due to the mood of their captain, the Russians won the final match over Brazil: in the first set when the score was 23:16 in favor of their rivals, the Russians scored 7 points in a row with Grankin serving and they pulled out a losing party, broke down the Brazilians who lost the following two parties sets.
Sergey spent the season 2005/06 playing with "Luch" (Moscow). Since fall of 2006 he has been playing with "Dynamo" (Moscow). Grankin made his debute to the Russian Senior national team on July 16, 2006 in the second Moscow World League match against the team of France, coming on as substitute. On July 28 in Genoa he made his first appearance in the starting line-up of the team which defeated the same day the Italians by 3:0.
Since the 2006 World Cup Grankin has been in teh starting line-up of the Russian side. In autumn 2009, he was elected captain of the Moscow "Dynamo".