Born in Watford, Hertfordshire, Kinsella spent eight years in the Arsenal's youth academy, representing the club from under-8 to under-16 levels, before being released and joined Aston Villa's academy in 2011. During his first season with the club, Kinsella played in all but one of the club's matches in the 2011–12 NextGen Series. Despite missing the group games of the competition during the 2012–13 NextGen Series, he later returned to help the club win the competition. Kinsella was called up to first-team training by manager Tim Sherwood in March 2015 following injuries to regular left backs Aly Cissokho and Kieran Richardson. He was named in the matchday squad for the first time on 7 March 2015 for Villa's FA Cup quarter-final tie against West Bromwich Albion, though he remained an unused substitute in a 2–0 victory. On 26 March 2015, Kinsella joined League Two club Luton Town on loan until the end of 2014–15. He made his professional debut two days later, playing the full 90 minutes of a 2–1 defeat away to Northampton Town. He completed the loan spell with three appearances. Following his return to parent club Aston Villa, Kinsella signed a new one-year contract in June 2015. On 18 February 2016, Kinsella joined National League club Kidderminster Harriers on a one-month loan. He debuted two days later, starting Kidderminster's 2–2 draw at home to Chester. Kinsella made six appearances before extending his loan with the club on 21 March until the end of 2015–16, finishing the loan spell with 13 appearances. After the end of the season, Kinsella announced Aston Villa had not offered him a new contract and left the club after five years.
Colchester United
During the summer of 2016, Kinsella received offers from two English Football League clubs, but both fell through. He then spent a week training with Swindon Town, and his former loan club Luton. After impressing in two trial matches against Crystal Palace and Ipswich Town for Colchester United, Kinsella signed a one-year contract with the League Two club on 29 July 2016. He debuted in Colchester's 1–1 draw away to Hartlepool United on the opening day of 2016–17. Kinsella made 14 appearances during the early months of the season, but sustained an injury in the latter, a 0–0 draw with Newport County on 8 October. He required surgery on his ankle that ruled him out of action for three months. Kinsella ended the season with just one further appearance following his injury, bringing his total to 15 for the season. He signed a new one-year contract with Colchester on 29 June 2017.
Aldershot Town
He joined National League club Aldershot Town on loan for one month on 4 January 2018. Kinsella made his Aldershot debut two days later in their 2–1 away win over Dover Athletic. On 31 January 2018, Kinsella signed for Aldershot permanently on a contract until the end of 2017–18, after leaving Colchester by mutual consent. He signed a new one-year contract with the club on 11 May 2018.
