Cunningham will lead the group's contact centre sales operations across Horsham, Belfast and Dublin, including responsibility for the newly created dedicated trade reservations team.
Bringing more than 20 years' experience in the travel sector, Cunningham joins from Travelbag, where she most recently held the role of Divisional Sales Manager, leading a team of 38 across retail stores and contact centre operations.
Her background in leisure travel sales, customer service and operational delivery will support SHG's continued focus on strengthening its reservation teams and enhancing support for both customers and trade partners.
The appointment comes alongside the promotion of Jorge Quibell to Director of Trade Partnerships, effective from 1 August.
Quibell, who was previously Head of Trade Partnerships, will continue to lead SHG's trade strategy, oversee its expanded trade partnerships team and develop relationships with agent partners across Sovereign Luxury Travel, American Holidays and Citalia.
Quibell said: "Travel agents are central to our growth, and we hugely value the support we continue to receive from partners across the UK and Ireland. My focus will be on building those relationships further, making sure agents have the right tools, support and access to our teams, and continuing to champion the trade across Sovereign, American Holidays and Citalia."
The senior appointments follow a period of strong growth for SHG, with trade sales up 57% year on year in June and currently tracking around 50% ahead year on year in July.
Andy Freeth, Specialist Holidays Group Chief Executive, said the "well-deserved" promotion and appointment underline the company's commitment to its agent partners.
"We know how important it is for agents to have access to expert support, responsive service and the tools that make it easy to do business with us," he said.
"Jorge and Maria give us the experience, expertise and relationships which, alongside our expanded team and investment in our new trade portal, demonstrate our focus on strengthening our partnerships with agents and supporting their growth."