Jones replaces Jack Trengove in the role after the former number two draft pick stepped down in November while Grimes will enter his third year as one of the Demons' leaders.
The elevation of Jones, who had a taste of the captaincy last year when he covered for the injured Grimes between Round 7 and 14, comes as little surprise.
The 26-year-old was a standout for Melbourne in their disastrous 2013 and while he did not possess the official title of 'captain', he lived up to it in every sense as he led from the front on a weekly basis.
Jones won his second consecutive club best-and-fairest award last year on the back of a team-high 509 dispsoals, 131 clearances and 241 contested possessions.
James Frawley, Trengove, Colin Garland and Mitch Clark round out the Demons' six-man leadership group.
Melbourne's entire playing list voted on the leadership group and from there coach Paul Roos, his coaching staff and CEO Peter Jackson recommended to the board that Jones and Grimes be the club's co-captains.
Jones has played 157 games since debuting for Melbourne in 2006 and Grimes has 68 matches under his belt in six seasons at the club.