Kingsley attained skills in sculpturing and was well known for his crafts in crafting dental prosthesis. He won two gold medals in a row at World's fair Competitions in New York City (1853) and Paris (1855). He published a report of the case, a child with a V-shaped alveolar arch, in 1858 in the New York Dental Journal. In 1859, Kingsley created an artificial palate of soft vulcanized India rubber for his first patient with a cleft palate. He eventually moved into teaching and became the Founder of the New York College of Dentistry, serving as its first dean from 1865 to 1869. Kingsley was also known for his work related to the vulcanite palatal plate which consisted of anterior incline which allowed a person to bite forward with their lower jaw. His appliance was later modified by Hotz and it was known as "Vorbissplatte".