Abdullah played four seasons with the Minnesota Vikings before joining the Chiefs in 2013.
In seven seasons, he made 289 tackles in 97 games with six interceptions and two touchdowns.
Abdullah, a devout Muslim, interrupted his career in 2012 to make a pilgrimage to Mecca during the Hajj. He was signed by the Chiefs the following year.
"The three years I spent playing for KC may have been the most enjoyable football experience in my entire life. Thank you," Abdullah wrote on Instagram.
Abdullah's retirement comes against a backdrop of ongoing concern over concussions in the NFL. In April last year, the NFL agreed to settle a lawsuit and pay $765 million to about 5,000 former players over health claims linked to concussion and head injury.