Liam's uncle, Maurice Ahern (1899–1950), was captain of the East Cork 4th Battalion Number One Brigade of the IRA.
Another son, auctioneer Maurice Ahern was a long-standing Fianna Fáil councillor for the Midleton electoral area of Cork County Council from 1979 to 2009.
Liam's granddaughter Ann-Marie Ahern is a Fianna Fáil member of Cork County Council since 2020.
At the 1973 general election, he again contested Cork North-East, where he came fourth out of the four successful candidates,[4] unseating the sitting Fianna Fáil TD Seán Brosnan.
"[5] He died in July 1974 at the age of 58, triggering a by-election on 13 November 1974 in which his seat was retained for Fianna Fáil by Seán Brosnan.