Grimston served as president of the British Columbia Amateur Hockey Association from 1942 to 1947, and was credited by The Canadian Press for keeping junior ice hockey operational despite the lack of facilities and dwindling attendance during World War II. He also sat on the national committee to oversee minor ice hockey in Canada, and sought for the transparency of finances in amateur hockey. He served as a director for the New Westminster Royals and played a leading role in their successful bid to join the Western Hockey League in 1952. He was a vocal supporter of the Penticton Vees and led a committee to oversee travel arrangements for the team as it won the 1955 Ice Hockey World Championships for Canada. He was a member of multiple community service groups, served four terms as chairman of the New Westminster Parks Commission and was president of the local Rotary Club. He sought for the construction of the Queen's Park Stadium and to expand and beautify city parks. Grimston died in 1955 at age 55, was posthumously recognized by New Westminster with Grimston Park named in his honour the same year, and was described by Jimmy Dunn as "one of the most colourful and aggressive presidents the CAHA ever had".