Pennies, which Dyson will join in September, allows customers online or in store to add a charitable donation of a few pence to a selected charity when paying for goods or services. It raised £2.8m in 2014 for more than 100 charities, nearly twice the total of two years previously.
Dyson has held his current role since January, having joined the charity as a senior PR manager in February 2008.
He also spent four years working in comms for disability charity Scope's comms team, and two prior years in Scope's fundraising team.
Dyson has also been a trustee of membership network CharityComms, and created the Third Sector PR & Communications Network, a Facebook networking group that now has nearly 2,500 members.