On Friday, Joe Exotic was sentenced to prison for the second time over the plot to kill his rival.
Exotic, whose given name is Joseph Maldonado-Passage, was sentenced to 21 years in prison by a federal judge in Oklahoma City.
Exotic won an appeal last year in which he argued the judge wrongly counted his two murder-for-hire convictions.
The convictions should be counted together because they shared a common criminal objective and were part of the same conduct, according to the appeals court.
John M.Phillips, a lawyer for Exotic, said in an email that they were dissatisfied with the court's decision and would appeal.
Exotic maintained his innocence in a statement that he read to the judge. He said that the truth was not told.
Exotic was diagnosed with cancer and begged to be released.
Baskin told the judge that Exotic was still a threat to her and her family.
Baskin said that the judge was fair and that she was happy with the outcome.
Exotic, the zookeeper, tried to hire two assassins, including an undercover FBI agent, to kill Baskin, an animal rights activist who had criticized his treatment of big cats.
Exotic was found guilty of faking wildlife records and of killing and selling tigers, both of which are rare.
Exotic's defense attorneys were confident that Donald Trump would pardon him before he left office.
Baskin didn't respond to a request for comment.