Isembold Took was the son of Gerontius Took and Adamanta Chubb. He was born in T.A. 1242 and died in 1346. It is unknown who he married but he had many descendants, also unknown. Isembold was the younger brother to Isengrim III Took, Hildigard, Isumbras IV and Hildigrim and the older to Hildifons, Isembard, Hildibrand, Belladonna, Donnamira, Mirabella and Isengar.
Isenbold was added to the fourth draft of the Took genealogy as the fifth son of Gerontius with the birth and death year as shown in the genealogy in The Lord of the Rings.
In the fifth and final as published in LotR he was given many descendants but none of them named.