Heeding the advice of the Metropolitan’s director, Francis Henry Taylor, Parker traveled abroad in 1948 to gain experience by working as an apprentice in museums across Europe.
During his time abroad, he studied under Pierre Verlet and Sir John Pope-Hennessy, art historians and curators at the Louvre and the Victoria and Albert Museum, respectively.
Parker’s specialization in French furnishings and interiors of the seventeenth and eighteenth centuries, earned him a guiding role in the installation of the Wrightsman Galleries, an extensive ensemble of period rooms.
Parker wrote scores of articles on subjects ranging from Rococo furniture to gilt-bronze ornaments, as well as assisting in the research and writing for several publications devoted to the Kress, Sheafer and Wrightsman collections.
Parker felt that the decorative arts were, in a sense, an undiscovered realm, and his meticulous research efforts and concern for historic interiors and objects led to several important findings.
It was Parker, for example, who discovered that windows in the Metropolitan's Sagredo bedroom had originally been located on the opposite wall, but were interchanged during installation and relocation to allow for natural and then electric light.