Shelaine Green, chairwoman of the Guernsey Disability Alliance (GDA), said what started as a group of volunteers “needed to be professional”.
She said States departments wanted more input from the disabled community since the island’s disability strategy had been approved.
Ms Green said the role would ensure the group was “here for the long term”.
She said: “There’s a lot to deliver and in that process, we are the voice of disabled people… attitude change takes a very long time.”
The executive director post is due to be funded for two years by the donation from the Guernsey Community Foundation.
Wayne Bulpitt, the new chairman of the foundation, said it was the largest single donation the group had made so far.
He said the foundation had been impressed by the GDA’s hard work and its ambition.
The donation was announced on Thursday at an event held to mark Deputy Arrun Wilkie’s appointment as the States Disability Champion and Jane Stephens being appointed his co-chair on the island’s Disability and Inclusion Strategy Steering Group.