Lord Rathdonnell was married to Anne Lefroy, sister of Sir John Henry Lefroy, and they lived between Drumcar, County Louth, and their London house at 80 Chester Square. The marriage was childless. Rathdonnell was also an uncle of the Arctic explorer Sir Francis Leopold McClintock. Lord Rathdonnell died in May 1879, aged 80. He was succeeded in the Barony according to the special remainder by his nephew Thomas McClintock-Bunbury, who notably served as Lord Lieutenant of County Carlow and as President of the Royal Dublin Society.
Arms
Coat of arms of John McClintock, 1st Baron Rathdonnell
Crest
A lion passant Proper.
Escutcheon
Per pale Gules and Azure a chevron Ermine between three escallop shells Argent.
Supporters
Dexter a lion and sinister a leopard both Proper each gorged with a collar Ermine and each charged on the shoulder with an escallop Argent.