He was born on February, 5, 1951 in the village of Noviye Verkhissi, Mordovskaya ASSR.
He began his career in 1968 as a combine operator in one of the collective farms of the Insarsk district. In 1968 he entered the Mordovia Ogaryev State University and in 1973 got the qualification "engineer of the electronic equipment".
From 1977 till 1986 he rose from the position of the Secretary, the Second Secretary to the First Secretary of the Mordovia Regional Komsomol Committee.
In 1986 he was appointed to the post of the First Secretary of the Tengushevsk CPSU Regional Committee of the Mordovskaya ASSR, and in 1990 - the Second Secretary of the Mordovian CPSU Committee.
From 1992 till 1995 he was the Chairman of the Personal Estate Fund of the Mordovia Republic.
In 1995 he was elected the Head of the Republic by the Constitutional Assembly of the Mordovia Republic.
In February 1998 he won the elections of the Mordovia Republic Head.
He was reelected president of Mordovia in 1998 and 2003 with 80% of the vote.
On May 10, 2012 Merkushkin resigned to become Acting Governor of Samara Oblast.
Wife - Merkushkina Taisia (born 10.09.1948). Sons - Alexandr (born 26.12.1974) and Alexei (born 20.06.1978).
His hobbies are billiards, chess, football, volleyball. He is fond of Russian folk songs.