He proved himself a very astute diplomat who outmaneuvered the British Embassy on several occasions during that extraordinary time.
A wrong step at the time might well have ended the American involvement in the peace process, but Gallagher proved himself an astute reader of the mood in Washington and ensured that Ireland's support for the breakthrough Gerry Adams visa was expressed in clear and concrete terms to the administration.
Gallagher's reward was the top job back in Dublin, where he assisted several leaders in pursuit of the Holy Grail of the peace process.
He was a constant player during that period, providing an institutional memory and insights to each new politician who became involved in the issue.
Gallagher came of age at an amazing period for Irish diplomacy, with the entry into the European Union greatly adding to the workload of the Irish diplomatic corps, the peace process and the global engagement in issues such as world hunger.
Suffice to say that in every arena he distinguished himself and made his mark in each posting. A native of Leitrim and a fanatical follower of that team's fortunes, Gallagher is hardly likely to retire to the golf links just yet.
Like other former diplomats there are bound to be many business offers on the table to use his expertise.
THE new secretary of the Department of Foreign Affairs will be announced next month according to reports, and it appears there is no clear frontrunner.