Geeson was one of three new trustees to join the institute's board. Paul Kane, fundraising officer at the Northern Irish development charity Trocaire, and James Hammond, of the consultancy Brand Halo, were the others.
Joe Saxton, who will stand down as chairman of the institute next year, used the annual meeting to emphasise the importance of the Gift Aid consultation.
The consultation was launched by the Treasury to improve the use of Gift Aid, especially by smaller charities. The three-month process will conclude on 30 September.
The AGM also saw the Charities and Trustee Investment (Scotland) Act 2005 incorporated into the institute's memorandum and articles.