Here, Press Association Sport looks at some of the issues the three-time major winner will face in attempting to retain the trophy.
How to negate home advantage
Six of the last seven contests have been won by the home side and, as Harrington himself has pointed out, it took a "Miracle at Medinah" for the one away victory to occur. Harrington has already floated the idea of a neutral figure being put in charge of course set-up, but acknowledges that is not likely to happen any time soon. The good news is that Harrington believes some American players "aren't that happy" with the links-style course at Whistling Straits, where Martin Kaymer won the 2010 US PGA Championship.
Number of wild cards
The number of wild cards has varied in recent years, with Jose Maria Olazabal having just two in 2012 and Paul McGinley and Darren Clarke allotted three each in 2014 and 2016 respectively. Thomas Bjorn had four last year and was undoubtedly glad of them as Sergio Garcia, Henrik Stenson, Ian Poulter and Paul Casey all failed to qualify automatically. With many of Europe's big names increasingly competing on the PGA Tour, Harrington could opt to have another qualifier from the World Points List, but keeping the same system is more likely.
Choice of vice-captains
Harrington has been a vice-captain himself for the last three contests, as well as playing six times since making his debut at Brookline in 1999. Cynics might suggest that captains choose their vice-captains simply based on who their friends are, but Harrington appears to appreciate the mix of characters required in the European team room. Speaking about his experience at Le Golf National, Harrington said: "You are always learning and it was a nice balanced vice-captaincy with different personalities; some good emotions, some good thinkers."
How to get the best from Rory McIlroy
McIlroy has played in every possible session in his five Ryder Cup appearances to date, but won just two points from his five matches in Paris and has now lost his last two singles contests – against Patrick Reed and Justin Thomas – when sent out first. McIlroy admitted he "hit a wall" at Hazeltine and was clearly not on top form at Le Golf National, so it will be interesting to see if Harrington becomes the first captain to use him more sparingly.