The heir to the British throne told CNN affiliate ITV News that, while it was not "everyone's cup of tea," there was a place for regulated commercial hunting of "old, infirm animals" if the proceeds raised from licenses went back into protecting endangered species.
"So when (an animal) is infertile, he's at the end of his life, if somebody out there wants to pay that money -- and it wouldn't be me -- but if somebody did, then as long as that money goes back into protection of the species then it is a justifiable means of conserving species that are under serious threat," he said.
The remarks from the Duke of Cambridge, a prominent conservation supporter, were condemned by UK-based conservation group Lion Aid.
The group said it was "very sad" to hear the 33-year-old royal's stance.
"With likely (fewer) than 15,000 wild lions left in Africa, there is no place for commercial hunting of lions. With an estimated 1,500 wild male lions in existence and with current 'offtake' for trophy hunting of 300 per annum, continued trophy hunting cannot be deemed as sustainable," Pieter Kat, the group's director, said in a statement.
"A lion of six years of age is not 'post-reproduction,' in fact it is just coming into his maturity, yet it is at this age most African countries offer these prime males as trophy."
The remarks came shortly after William unveiled plans to tackle wildlife trafficking. The plan tasks transportation leaders with cracking down on trafficking routes.
"If current trends continue, the last wild African elephants and rhinos will be killed before my daughter Charlotte reaches her 25th birthday," he said in a speech to mark the initiative.
"The question is: can we be bothered to do our bit? By signing this declaration, you, the leaders of some of the most important transportation companies and agencies on earth are answering with an emphatic, 'yes'."
In 2014 the prince was criticized
for participating in a deer and wild boar hunt in Spain, shortly before speaking out about the evils of illegal hunting.
Kensington Palace had no comment to make on the criticism Wednesday.