Opener Sehwag cracked two sixes and 22 fours in his third Test century in 10 matches as India posted 175 for no loss at tea on the opening day after electing to bat on a newly laid pitch at the Wankhede Stadium.
Sanjay Bangar played a supporting role as he contributed just 44 in a big stand for the opening wicket. He played only one big shot in his 171-ball knock, lifting left- arm spinner Ryan Hinds for a straight six.
The stand was India's highest for the opening wicket against the West Indies, eclipsing the previous best of 153 between Sunil Gavaskar and Chetan Chauhan at this venue in 1978-79.
Sehwag, who turns 24 in 10 days, never allowed the West Indian bowlers to dominate with his wide range of attacking shots as he batted comfortably against both pace and spin during his 181-ball knock.
The Delhi batsman completed his half-century off 85 balls in the last over before lunch when he square-drove left-arm fast bowler Pedro Collins for his 11th boundary.
He took 53 deliveries more to complete his hundred, lofting part-time seamer Wavell Hinds over mid-wicket for his 19th boundary. He then went on to surpass his previous best of 106 against England at Trent Bridge in August.
West Indies skipper Carl Hooper, playing his 100th Test, used all of his specialist bowlers in short spells in hot and humid conditions but none could provide the breakthrough.
The pitch had neither pace nor bounce for fast bowlers even on the first day of the match and the Indian openers made the most of the conditions to give their team a solid start.
Sehwag played attractive shots against both seamers and spinners, starting with two successive boundaries in Collins's opening over.
He then took two fours off Cameron Cuffy and three in an over off leg spinner Mahendra Nagamootoo, who hardly turned the ball in the first two sessions.
Sehwag continued to frustrate the West Indies who had to use as many as seven bowlers in an unsuccessful bid to break the stand. He struck the first six of the match, hoisting Nagamootoo over long-off.