Tenacious midfielder was a regular under Darrell Clarke during the 2019-20 season having won the 2018/19 Young Player of the Season award.
Colchester-born Kinsella first joined the Saddlers aged eight and was named Apprentice of the Season in 2013/14.
He made his first-team debut in a goalless draw with Bradford in August 2014 and scored his first career goal in a 2-0 victory over Burton the following October.
Capped by Republic of Ireland at Under-19 and Under-21 level, he helped our Development Squad win the Central League North West Division title and Walsall Senior Cup in 2016/17.
He made 24 appearances the following season and featured 39 times in 2018/19, scooping the Goal of the Season prize for his FA Cup stunner at Sunderland.
The 24-year-old signed a new deal in the summer of 2019 and was a regular under Darrell Clarke. He made his landmark 100th Saddlers appearance against Scunthorpe United in September 2019.