The deal is reportedly worth $36 million, including $20 million in guaranteed money.
The 24-year-old Casey has been a solid contributor for the Titans since they picked him in the third round of the 2011 NFL entry draft.
Casey had 55 tackles and 10 1/2 sacks in 2013.
"We are excited to come to an agreement on an extension with Jurrell," said Titans general manager Ruston Webster.
"This is something Jurrell has earned not only with his play on the field but his work ethic as well.
"We appreciate Jurrell's professionalism through this process and look forward to many good years to come."