Knight Riders, the most successful team in the history of the Caribbean Premier League with four titles, had finished bottom of the league stage last year and failed to make the playoffs for the first time.
Simmons has previous coaching experience in the CPL as well, and in his most recent stint, he won the title with Barbados Royals, who were then known as Barbados Tridents.
Simmons has had two stints as head coach of West Indies, with his most recent one ending with their tour of Australia in December last year. He then went on to coach Dubai Capitals in the inaugural season of the International League T20, leading them to the playoffs.
Apart from West Indies, Simmons has also coached Zimbabwe, Ireland and Afghanistan.
CPL 2023 gets underway on August 16, with Knight Riders playing their first game on August 19 against St Kitts and Nevis Patriots.
Source: ESPN Crickinfo