Born in Wilkes-Barre, Pennsylvania, Dean attended the University of Chicago from 1908 to 1910. Dean then went to work in the Chicago office of landscape architect Jens Jensen, and subsequently drafted maps for a cartographer. Upon her arrival in New York City, she worked for various architects, including Aymar Embury II. Dean designed gardens for many distinguished Long Island residences, including Grey Gardens around 1913. In 1915 she opened her first New York office, and maintained an independent office adjacent to her residence upon her marriage to Embury in 1923. The two collaborated with architect Lusby Simpson, Gilmore Clarke of Clarke & Rapuano, and Betty Sprout on the redesign of Bryant Park in 1934. Dean’s designs showed a modernist sensibility and featured simple yet functional spatial divisions, well-chosen garden details, and a harmonious relationship with architectural elements.
Dean contributed to such periodicals as The Garden Magazine, House and Garden, House Beautiful, and Country Life in America. In the late 1920s she was garden editor for the women’s magazine The Delineator. In 1917 Dean published The Livable House, Its Garden, a companion volume to Embury’s book The Livable House. She became a member of the American Society of Landscape Architects in 1921. In 1929 Dean became the first woman to be awarded the Architectural League of New York’s Gold Medal for three gardens she had designed in Grosse Pointe, Michigan. These gardens embodied her stylistic signature, with their series of enclosed garden rooms; thoughtfully composed mixtures of trees and shrubs and of evergreen, deciduous, and native species; and simple color combinations. Dean passed away at the age of 43 and was buried in Cedar Lawn Cemetery in East Hampton, New York.