Between 1967 and 1981, Peter MacLachlan served on almost every committee of the Board of Governors, and was chairman of several. Perhaps his two most valuable contributions were his reorganization of the Business Administration of the School, during his time as chairman of the Finance Committee, and his leadership of the Ad Hoc Committee of 1978, which planned the redevelopment and renovation of the whole area of Gooderham & Dean's Houses. MacLachlan was very much at the centre of the changes and expansions that took place during the 1970's. Reflecting his philanthropic work in other areas, he believed strongly in the continuing religious observance of the School, the exercise of care and compassion over its members, and the furtherance of its cultural and artistic life. MacLachlan died in 1981.