Montessori in the United States
During the late 1950s, an educational theory study group affiliated with John Carroll University and Ursuline College began discussing the writings of Nancy Rambusch, an American educator who studied the Montessori Method in London. Mary Ruffing, a member of the group, invited Nancy to come to Cleveland to give a talk about her school, Whitby Montessori (the first Montessori school in the United States), and about Maria Montessori. Mary and her husband Jim visited Whitby, and their enthusiasm inspired the study group to found the Cleveland Montessori Association (CMA) in 1959. They began the process of finding sites and hiring qualified teachers to open Montessori classrooms in Cleveland. Betty Hissong and Joan Ducas, two members of the study group, taught adult classes at Ursuline College to cultivate an interest in Montessori education.

Ruffing's Beginnings
In July 1961, beginning with a summer orientation program, several Montessori Children's House programs opened in existing school buildings throughout Cleveland, first on the west side, then on the east side, making Ruffing the second Montessori school established in the United States. In 1964, Cynthia and David Ingalls became interested in helping to establish a stable location for CMA, purchasing property on Fairmount Boulevard and leasing it, with the cottage located on it, to CMA for $1 a year. Jim and Mary Ruffing had become deeply involved as leaders in the American Montessori movement: Mary as the school's first Principal, and Jim, as a leader in American Montessori teacher training. When they moved away from Cleveland in 1969, the Board changed the name from Cleveland Montessori School to Ruffing Montessori School in their honor. Through the continued philanthropy of the Ingalls family, a second preschool classroom was constructed on the Fairmount Boulevard property in 1970. In 1971 the Ingalls donated the land and existing buildings, as well as funds to construct an additional building to house elementary classes. In recognition of this generous support, the Cleveland Heights location was named the Ingalls Campus.

Creation of the Fairmount Montessori Association
As the scale of the citywide school grew, it was becoming increasingly difficult to administer split locations. The principal spent one day a week at the Ingalls campus of Ruffing, while maintaining an office on the west side. In 1977, the east side and west side locations became legally separate, and a new entity was formed, the Fairmount Montessori Association (FMA), to operate the Ingalls Campus.

David Kahn, who had been hired as an elementary teacher in 1973, became the first Principal of Ruffing under the FMA in 1977. During his tenure, Ruffing achieved a number of milestones: becoming state certified, adding a third preschool classroom, expanding school services to families and increasing enrollment. After developing a Middle School curriculum and securing backing from families and local foundations, the FMA Board purchased an acre of land from Beaumont School and began construction of a new Middle School and Upper Elementary classroom building which opened in 1982. This additional space made it possible to launch a day camp that year: Summer Ruffing It.

In 1984-1985, David Kahn transitioned from principal to head of the Ohio Montessori Training Institute in Cleveland, which offered preparation for elementary and preschool teachers leading to certification by the Association Montessori Internationale.

Continued Growth and Expansion
As a parent-operated school, volunteers and trustees had overseen many of the administrative functions of the school. The Board devised a joint headship plan to professionalize these functions and in 1985 John Long, a Middle School teacher, became Principal and Jan Katz, already on staff as Administrator, was appointed co-head for administration. In 1989, the Lower Elementary and Middle School buildings were connected by a new gymnasium/community center, which also included an art room, an after-school environment and expanded space for Middle School.

In 1991, John Long resigned to return to teaching in the Middle School and Marilyn Wright, an experienced teacher from the Middle School, served as Interim Academic Dean for the 1991-92 school year. Timothy Duax was Principal from 1992 to 1994, but then returned to his native Wisconsin. At that time, Ruffing teacher Robert Fleischhacker became Principal, without a change in the joint headship structure.

In 1999, the All Day Children's House was established to further serve the needs voiced by parents. In 2001, Gordon Maas was named Head of School, combining both administrative and academic leadership in one position. To achieve greater involvement in the Cleveland educational community for the school, Ruffing joined the Cleveland Council of Independent Schools (CCIS) and applied to become accredited by the Independent Schools Association of the Central States (ISACS), receiving full membership in 2006. The Parents' Association was formed to further build community among the parents; both the President of the Parents' Association and a faculty representative began attending Board of Trustees meetings in an ex officio capacity.

Green Redesign for the Entire Facility
In 2004, the Board began discussions about the need to redevelop the aging campus and voted to do so by following Leadership in Energy and Environmental Design (LEED) construction technology principles. After careful planning, the groundbreaking was held in June 2005. Conducted in three phases, the redevelopment project was completed in 2007, and enabled the school to unify a multi-structure campus, open a Toddler Community, offer a Siesta program, physically expandor replace all classrooms, dedicateimproved space for art, music, drama and world language, and most importantly, create a healthy and safe learning and working environment.

In 2008, the school joined OAIS (Ohio Association of Independent Schools) to collaborate and share resources with a state-wide presence in support of independent school education.