Throughout the school's years of growth, The Gladwyne Montessori School has been fortunate in the leadership of its dedicated administrators. For its first three years in the carriage house, the school was Board run with the guidance of head teacher and Board Chairman, Josie Sorlien. Cecile Benford succeeded her as head teacher for one year. Until 1968 Darcy Hall was the school's first non-teaching headmistress. When she moved to Canada, Hope Mitchell succeeded her.

In 1971, Virginia Mount became the first headmistress with formal Montessori training. During her administration, the school earned accreditation with the Pennsylvania Association of Private Academic Schools (1973-1974) and is the only Montessori school in Pennsylvania to belong to that organization. PAPAS conducted an evaluation in the fall of 1989 and praised the school for its educational programs for children. Kathleen Dzura was named headmistress in 1976-1977. Kathleen had been a teacher trainer at the AMI (Association Montessori Internationale) training center at Ravenhill Academy in Germantown, which closed in 1976. Kathleen left the school in June 1979 and Kathleen Young was acting headmistress until 1980.

Anne R. Shields (later Anne S. Kane) was hired by the Board in the Spring of 1980. Her training in both primary and elementary Montessori brought strength and continuity to the entire Montessori program. Anne's 9 years of service to the school saw a period of growth and diversity of programs. In 1987, the school celebrated its 25th anniversary with a dinner dance at the Merion Cricket Club where five former headmistresses and several of the school's founders were honored.

Anne left the school in 1989 and Gerry Hartnett, assistant headmistress and elementary teacher, assumed the job of acting headmistress until a search committee could locate a replacement.

Annmarie R. Torres became the new headmistress in the Fall of 1990. Annmarie was a Montessori teacher and trainer at Ravenhill and brought tremendous vitality and enthusiasm to the school. During her tenure the school expanded to include an additional Stepping Stones and Primary class, a full time physical education teacher, a business manager, and a director of development. After School programs, a Summer Camp, Parent/Infant and Parent/Toddler programs are also recent additions to the school programs. In the Fall of 1994, The Gladwyne Montessori School hosted the first North American Montessori Teachers Association meeting in Philadelphia, which was attended by over 150 Montessorians throughout the country. In October of 1996, the school was host to administrators, teacher trainers and teachers as a tour site for the American Montessori Society (AMI) Conference held in Philadelphia. Annmarie retired in July of 1998.

In 1998, the Board hired Walter Ebmeyer, our first headmaster. Walter comes from a non-Montessori background, having been the headmaster at several K - 8 independent schools. His vitality, enthusiasm and vision carried the school to its next level, including the construction of the Rachel Savett Building.

Walter retired at the end of the 2002-2003 school year.

Usha Balamore succeeded him for 3 years, until 2006, bringing the school to new heights of enrollment and purpose, with themes of Growing in Goodness, Peace & Giving, and Community.

Robert Coombs was the Interim Head for the school year 2006-2007, the 100th anniversary of the Montessori movement.

        From 2007, the school is fortunate to have Abigail Miller as its head.