Between 2011 and 2014, Kirby took 180 wickets for Somerset before retiring due to an ongoing shoulder injury.
Following his retirement, he spent two years as the bowling coach at the club. In 2022, he took up the equivalent position with the Zimbabwe national team.
"The benefits of this experience will certainly aid me in any coaching role in the future and I can't wait to be able to bring these skills to Taunton, and help support what is an amazing squad of players."