Who was he?
John Scott Harrison occupies a unique place in American history; he was both son and father of United States Presidents. Harrison's father was William Henry Harrison, Indiana Territorial Governor and soldier who was elected ninth President as a Whig. His son was Benjamin Harrison, Republican Senator from Indiana and the twenty-third President. Both of the presidential Harrisons also held the rank of Brigadier General in the U.S. Army.
The Harrison we are concerned with here seems to have been cut from a different bolt of cloth from that of the Presidents. He was born in 1804 and, rather than take up the sword, studied medicine before becoming a farmer in Ohio (not Indiana). After the death of his first wife, Lucretia, in 1830, he married Elizabeth in 1831 and Benjamin was born to them in 1833. Apparently, quiet family life on the farm suited John well; his only dip in the political pond occured after Elizabeth's death in 1850. From 1853 to '57 he served two undistinguished terms as Representative from Ohio -- first as a member of the moribund Whig party, then re-elected as one of the new Republicans. After being defeated for a third term, he retired to his farm and died there in 1878.
Whether he was constitutionally weak, or merely unambitious, John Scott Harrison's only claim to a part of history appears to be as a critical link in a chain of Harrisons that has existed in American political life from the signing of the Declaration of Independence (his grandfather, also a Benjamin) well into the 20th Century (his great-grandson, also a William Henry Harrison, Representative from Wyoming). He must have spent little time basking in reflected glory; his father died after only a month in office and he did not live long enough to see his son succeed in politics.
I care because... ?
Bar bets. Assuming that your mark has had a drink or two more than you have had, you ought to be able to win the next round by slurring the crucial preposition in this trivia question: "Father and son of Presidents?" Wouldn't you pipe up with the Bushes or the Adamses after knocking a few back? Just don't bet real money; sucker-bets piss people off.
Sources:
HARRISON, John Scott (1804-1878) Biographical Information
http://bioguide.congress.gov/scripts/biodisplay.pl?index=H000272
Harrison Family
http://www.surf-ici.com/harrison/beninfo.html
Genealogy of the Presidents of the USA John Scott Harrison
http://users.legacyfamilytree.com/USPresidents/6517.htm