On 8 January 2017, making his first start for Chelsea since an EFL Cup defeat to West Ham United in October 2016, Terry was given a straight red card for a foul on Lee Angol as Chelsea beat Peterborough United 4–1 in the FA Cup third round. On 17 April, he announced that he would be leaving Chelsea at the end of the 2016–17 season. After Chelsea celebrated their Premier League victory, Terry played his 717th and final match for Chelsea on 21 May in a 5–1 home win over Sunderland, coming off in the 28th minute (the substitution board went up in the 26th minute, the same as that of his shirt number), and received a guard of honour from his teammates. In December 2019, Terry was voted in Chelseas' team of the decade as voted for by Chelseas' fans.
On 3 July 2017, Terry signed a one-year contract with Championship club Aston Villa on a free transfer. He was appointed as the captain for the 2017–18 season. He made his debut for Aston Villa on 5 August 2017 in a 1–1 home draw with Hull City in the Championship. Terry scored his only goal for Aston Villa in a 2–1 victory over Fulham in the Championship on 21 October 2017.
Despite the praise he received in the media for his defensive skills, critical opinion on Terry's technical ability was frequently divided; throughout his career, he was often paired with an intelligent, more technical and more mobile ball–playing centre-back, such as Ricardo Carvalho at Chelsea or Rio Ferdinand with England, which complemented Terry's more physical playing style as a "stopper," and also provided cover for him, as his lack of pace saw him struggle at times in teams that played a high defensive line. While some pundits, such as Chris Wright of ESPN or Robin Bairner of Goal.com, have cited Terry's technique as a weakness, with Tom Sheen of The Independent also noting that his general reputation for lacking speed or elegance in possession and his reluctance to carry the ball out from the back saw him perceived as "a bit of a plodder when on the ball," others, such as Jamie Carragher and Jamie Redknapp, have instead argued that his ability on the ball and composure in possession was an underrated aspect of his game, which did not get as much attention as his tactical sense. During one of Terry's final matches for Chelsea, in a 2017 article for The Guardian, Barney Ronay noted that "Terry lined up at the heart of the central defensive three," and described him as: "A little heavier, clanking about like an eager old tin man, he still has an excellent touch although, had he played much deeper in the second half, he might have been best served bringing out a shovel and digging a trench in front of his own goal." In 2009, UEFA.com praised Terry for his ability to control the ball with his chest. Moreover, although Terry's passing was initially cited as being in need of improvement in his early career, his distribution throughout his career was also generally solid and reliable, which often saw him complete many passes throughout the course of a season with a high success rate, although he usually favoured making simpler short passes on the ground; Michael Cox described his distribution as "underrated" in 2015, however, while Redknapp and Carragher have both noted that Terry was also capable of playing long balls with either foot, despite being naturally right–footed, a trait which Sam Wallace and Tom Sheen of The Independent also noticed in 2011 and 2014 respectively, with the latter describing Terry as "an exceptionally two-footed footballer," who "will show off a range of passing with either foot." As Sheen notes, Terry's ability with either foot often allowed him to play as a left–sided centre-back in a four–man defensive line throughout his career. In 2011, Terry was the world's third best passer for players with over 1,000 passes, with a 91.6% pass accuracy rate. Only Barcelona player Xavi (93.0%) and Swansea City player Leon Britton (93.3%) were better. He also played in a three–man back–line on occasion, in particular in his later career under Chelsea manager Antonio Conte, although he struggled to adapt to this formation due to his lack of pace as a result of his advancing age. Despite his reputation as a defender, however, Terry has also drew criticism in the media for his involvement in several controversial incidents throughout his career, both on and off the pitch.