The agency won the account to assist on a raft of campaigns aimed at halting voter apathy, following a COI pitch.
The agency's first task will be to promote the local elections, which take place across England on 1 May. Two key groups that campaigning efforts will aim at are young people and ethnic minorities.
Earlier this month, the Commission revealed research showing that while more than one in three 18 to 24-year-olds never vote in local elections, they are far from politically apathetic. Eight out of ten people surveyed said they were interested in local issues such as crime, housing and health.
Fiona Longhurst, who reports to the Commission's director of media and public affairs Anne Hinds, heads the Band & Brown account team.
Band & Brown's sister agency iJack, which specialises in online PR, will be assisting on the account.