Since a great-uncle is the same generation as a grandfather, we can safely say no great-uncle of his was "well-known businessman in the capital at the time" of "an 18th century Dublin wig-maker".
Here's a family tree for him:
http://www.wargs.com/political/obama.htmlThere's a Falmouth Kearney, born Ireland, around 1832; and his daughter Mary Ann Kearney, born Tipton Co., Ind., 19 Sept. 1869. See
http://www.rte.ie/news/2007/0315/obamab.htmlAh yes - more detail in this story:
The Kearneys prospered in the 18th century, with John Kearney, a distant cousin, becoming provost of Trinity College and later bishop of Ossory.
Michael Kearney, described as Obama's sixth great granduncle, entered the guild of barber surgeons and periwigmakers in 1717, and was enrolled as a hairdresser in the freemen's rolls in 1718. He had the right to vote in elections to the city council in Dublin.
In the 1750s, "when the aristocracy tried to gerrymander elections in Dublin city council, to put in their own candidates", Michael Kearney was prominent among guildsmen in opposing them.
After the 1780s, the fortunes of this line of the Kearneys declined because of economic changes after the Act of Union and a downturn in the fashion of wig-making.
http://www.irishtimes.com/newspaper/ireland/2008/0807/1218047756312.html"