The 19th century is very difficult to translate from a Canadian to an American setting, to a great extent not just because the Governors-General were British noblemen, but due to the fact that they were for the most part very much active in British politics. The Marquess of Lansdowne had served in Gladstone's government prior to being GG of Canada, and afterwards, he would go on to serve as both Secretary for War and Foreign Secretary under Lord Salisbury and Arthur Balfour. The Marquess of Aberdeen was an active Liberal politician both before and after his stint in Canada, as were the Earl Grey. The Duke of Devonshire was a Liberal Unionist, serving in the government of Arthur Balfour as Financial Secretary to the Treasury, and he would later, as a Conservative, serve as Colonial Secretary under Bonar Law and Stanley Baldwin once his term in Canada ended.
If we try to find as good analogies as possible from Vincent Massey onwards, though...
1952-1959: Harry Hopkins
1959-1967: Dwight D. Eisenhower
1967-1974: John W. McCormack
1974-1979: George F. Kennan
1979-1984: Wendell R. Anderson
1984-1990: Geraldine Ferraro
1990-1995: Howard Baker
1995-1999:
Okay, can't come up with a good parallel for Roméo LeBlanc, and I got bored there and gave up.
In fact, looking at the Governors-General that Canada has had in the past 70 years, they're all surprisingly boring individuals... In many cases, they appear to be little more than quite obvious appointments as favours for political reasons.