A great-grandson of the Old Took through a minor line, Paladin owned farmlands around Whitwell - a village which, though it appears on no map, is known to have been close to Tuckborough in the western Green Hills. He married Eglantine Banks, and the couple had four children. Three of these were daughters (Pearl, Pimpernel and Pervinca), and the youngest was a son, Peregrin Took, commonly known as 'Pippin'.
The thirty-first Thain of the Shire had been Ferumbras Took III, who was unmarried and left no heir. As such, the line of descent from the Old Took's third son Isumbras IV came to an end, and the descent moved on to the line of his fourth son, Hildigrim. Thus the Thainship fell on Hildigrim's grandson Paladin. At eighty-two, Paladin was already old at this time, and as Paladin's only male child, Peregrin became the heir to the Thainship of the Shire.
Four years after his father's accession to the Thainship, this same Peregrin became embroiled in the events surrounding his friend Frodo Baggins, and joined Company of the Ring. During his adventures in Gondor, Peregrin would commonly be called 'Peregrin son of Paladin' following the conventions of naming in that land.
While his son was travelling in distant lands, Paladin faced a challenge of his own in the Shire, as Lotho Sackville-Baggins attempted to take control of the land of the Hobbits. As the legitimate Thain, Paladin refused to accept Lotho's authority, and when Lotho's ruffians were found in the Tookland, they were hunted and shot. So the Tookland remained independent while Lotho and later Sharkey took over the running of the rest of the Shire. After the return of Peregrin and his companions to the Shire, a hundred of Paladin's archers took part in the Battle of Bywater and helped to defeat Sharkey's Men, though the aged Paladin himself does not seem to have been at the battle.
The fact that Paladin is styled in full Paladin II tells us that there must have been a Paladin I earlier in the history of the Took line (or, just possibly, in the preceding Oldbuck line). Presumably Paladin II was named for this earlier Paladin, about whom we know essentially nothing. Assuming Paladin I was indeed a Took, which seems overwhelmingly likely, then he would have been Thain at some point between Isumbras I (Thain from III 2340 or S.R.740) and Isengrim II (Thain from III 2683 or S.R.1083). We know that there were eight unnamed Thains in this unrecorded period, and it follows that one of them must have been Thain Paladin I.