A product of the Fenerbahçe youth system, Demiral was signed by Portuguese side AC Alcanenensein in 2016. In January 2017, he was loaned out to Sporting B, and made his professional debut in the Segunda Liga for the latter club on 5 February 2017 in a 1–1 home draw against Famalicão. At the end of the season, he was signed outright by the club. On 15 August 2018, he joined Turkish club Alanyasporon loan. On 29 January 2019, he permanently joined Alanyaspor for €3.5 million. On 30 January 2019, joined Italian Serie A club Sassuolo on loan with an obligation to buy. He made his Serie A and club debut on 24 February, in a 1–1 home draw against S.P.A.L., and scored his first goals, both for the club and in Serie A – a brace in a 4–0 home win over Chievo –, on 4 April.
Juventus
On 5 July 2019, Juventus officially announced the transfer of Demiral from Sassuolo, on a five-year contract for €18 million. His salary was reportedly unfolded as €1.3 million per annum. He became the first Turkish player to play for the club. He made his club debut on 21 September, in a 2–1 home win over Verona in Serie A. He subsequently made his Champions League debut on 11 December, in the club's final group match, earning praise in the media for his performance as he helped Juventus keep a clean sheet in a 2–0 away win over Bayer Leverkusen. He scored his first goal for the club on 12 January 2020, the opener in a 2–1 away win over Roma, which saw Juventus secure the unofficial title of "Winter Champions;" however, he was later substituted for Matthijs de Ligt after sustaining an anterior cruciate ligament injury. As a result, he was expected to be ruled out for the remainder of the season, including Euro 2020.
Demiral is usually deployed as a centre-back, in either a three or four-man defence, although he is also capable of playing as a right-sided full-back. An aggressive and instinctive defender, his main traits are his physicality, tactical intelligence, and determination, which allow to excel at reading plays, and also enable him to anticipate or mark his opponents well. A tall and physically strong defender, he is also known for his ability in the air, which enables him to defend opposing crosses and clear the ball away from his own penalty area. Despite his tall stature and imposing physique, he is also a mobile defender, which allows him to make recoveries, win back the ball effectively, or restrict his opponents' movements when defending off the ball. Regarded as a promising young defender in the media, due to his characteristics, he has been compared to Nemanja Vidić, whom Demiral himself has also cited as an inspiration. Another one of his influences is his Juventus teammate Giorgio Chiellini, to whom he has also been compared. He has also been likened to former Juventus defender Paolo Montero.
Controversy
On 11 October 2019, following Cenk Tosun's goal in a 1–0 home win over Albania in a Euro 2020 qualifier, Demiral was one of the Turkish players who participated in a controversial "military salute" goal celebration. The same day, he stated his open support for the Turkish offensive into north-eastern Syria on Twitter; while his post was praised by supporters of the Turkish President Recep Tayyip Erdoğan, it also drew criticism from numerous football fans of Juventus on social media, as well as those of other clubs, some of whom asked for the club to take disciplinary actions against the player; others even demanded that Demiral be dismissed by the club.
