Guy Stair Sainty is British born, having grown up in Sussex before moving to New York in 1979. After studying at Westminster School, in Rome and at the College of Law, Guy joined a London gallery specializing in 19th century European painting. He opened his first public gallery in New York in 1982 and quickly made his name as a specialist in 18th and 19th century French painting, before gradually expanding into Spanish and Italian painting of the 17th, 18th and early 19th centuries. Guy served for seven years as a member of the Art Advisory Panel of the Commissioner of the US Internal Revenue Service, is a member of the Art Dealer's Association of America and a member (and former Vice-President) of the Private Art Dealer's Association. Married to Elizabeth Pierson Sainty, he is the father of six children, but manages to find time for the study of the history of Orders of Chivalry, among other interests, and has published many article and three books on the subject.

Mercier Kinney, the child of two diplomats, lived in Rome, New York, Caracas, Florence, Copenhagen and Brussels by age twenty. She studied History of Art, and Iconography and Semiotics at Sarah Lawrence College, Languages at Middlebury College, and continued graduate work in Renaissance Painting. She worked in the Sculpture department at the Smithsonian's Hirshhorn Museum and then at a contemporary SoHo gallery prior to joining Stair Sainty Matthiesen. She was the New York gallery’s Director for many years, before taking up the position of Director at Stair Sainty, London.