In 1820 he became assistant to Coenraad Jacob Temminck at the Leiden Rijksmuseum van Natuurlijke Historie.
He then travelled to Java, then part of the colonial Netherlands East Indies, with his friend van Hasselt, to study the animals of the island, sending back to the museum at Leiden 200 skeletons, 200 mammal skins of 65 species, 2000 bird skins, 1400 fish, 300 reptiles and amphibians, and many insects and crustaceans.He described many new species and new genera of amphibians and reptiles.In 1821 he died in Buitenzorg (now Bogor) of a liver infection brought on by the climate and overexertion.
He had been less than a year in Java.
Johan van Hasselt continued his work collecting specimens, but died two years later.
The partners are buried in a single grave in the Botanoical Garden, Bogor, marked with a small column.
Several species have been named to commemorate his work as naturalist and zoologist:
Fishes
Bluespotted stingray or Kuhl's stingray, Neotrygon kuhlii
Kuhl's loach or kuhli loach, Pangio kuhlii
Kuhlia, a genus of marine fish, flagtailHerpetofauna
Kuhl's Creek Frog or Large-headed Frog, Limnonectes kuhlii, found in Southeast Asia
Kuhl's forest dragon, Gonocephalus kuhli, a lizard found in Indonesia
Kuhl's Flying Gecko, Ptychozoon kuhli, a gecko found in Southeast AsiaBirds
Rimatara Lorikeet or Kuhl's Lorikeet, Vini kuhlii lorikeet in islands of the South PacificMammals
Axis kuhlii, Bawean deer
Callithrix kuhlii
Eptesicus kuhli, synonym of Eptesicus nilssonii
Pipistrellus kuhlii, Kuhl's Pipistrelle
Sciurillus pusillus kuhlii
Scotophilus kuhlii