For anyone interested in doing therapy work with their Leonberger, a good training base will be required. Because of their size, Leos must be under control and responsive to calm commands. A heavy paw swat or a boisterous greeting could easily injure an invalid patient or someone in delicate health. There are a number of organizations that certify dogs for therapy work, where you can find information on how to prepare your dog for certification.

LCA has a Therapy program offering a Therapy title.

Therapy dogs are trained to provide affection and support to humans. They visit hospitals, assisted living homes, courtrooms, counseling offices, schools, airports, and other facilities where they offer comfort and relieve stress.
In addition to providing opportunities for petting and support, some therapy dog/handler teams work with healthcare professionals to improve treatment outcomes (animal-assisted therapy) or participate in literacy (read-to-the-dogs) programs.
Therapy dogs do not enjoy special rights of access to housing, travel, or entry into businesses that do not permit pet dogs. Their training differs from that of service and emotional support dogs, who are trained to focus on a single person; therapy dogs interact with many people in different environments for short periods.

Therapy Article 

Starting in Therapy