Ballance, who switched allegiance last year and has already played for Zimbabwe in limited overs internationals this year, scored 137 runs to help them declare on 379-9 in reply to West Indies’ first innings tally of 447 for six declared.
The left hander brought up his ton with a six over deep square leg as he and Brandon Mavuta (25) put together a 135-run partnership for the eighth wicket, hauling Zimbabwe out of trouble after they had slumped to 192-7.
Mavuta, who claimed a maiden five-wicket haul on the first two days of rain-affected play, made 56 runs before being bowled by Jason Holder on a flat deck.
West Indies lead by 89 runs going into the final day on Wednesday. They were 21-0 in their second innings at the close of play on Tuesday.
Harare-born Ballance, who moved to England as a schoolboy, was able to switch allegiances under International Cricket Council rules as a player can change between two different full member nations after a three-year stand-down period.
Ballance made 23 test appearances for England between 2013 and 2017, scoring four centuries.
He joins Kepler Wessels as the only players to have scored centuries for two countries. Wessels did so for Australia and South Africa.
