Tierney was crowned PFA Scotland Young Player of the Year for the second consecutive season on 7 May, making him the first to achieve this since Craig Levein in 1986.
1997
Kieran Tierney (born 5 June 1997) is a Scottish professional footballer who plays as a left-back or centre-back for La Liga club Real Sociedad, on loan from Premier League club Arsenal, and the Scotland national team.
Kieran Tierney was born on 5 June 1997 in Douglas on the Isle of Man, and moved to Wishaw in Scotland aged 10 months.
He supported Celtic as a child and signed for the club when he was 7 years old.
He was educated at Motherwell schools St Brendan's RC Primary and Our Lady's High (one year group behind fellow footballers, twins Nicky and Chris Cadden) then attended St Ninian's High School, Kirkintilloch, which has a development partnership with Celtic.
He has spoken of his hope of emulating the late Tommy Gemmell, a member of the Lisbon Lions team who also grew up in Wishaw (specifically, Craigneuk) and played in the same position.
He progressed through the various youth ranks and earned a reputation as a dependable wide player in the club's development squad, both in defence and attack.
2014
He travelled with the first-team squad on a pre-season trip to Finland in August 2014, and made his debut in a friendly against Tottenham Hotspur there.
Although Celtic lost, Tierney described his first appearance for the first team as a "dream come true".
He continued to play in the development squad throughout 2014–15, and in October 2014 during a Development League match against Heart of Midlothian he scored a goal from the edge of his own penalty box.
2015
Tierney came through the Celtic youth system and made his first-team debut in April 2015, and his full international debut in March 2016.
Tierney made his competitive senior debut for Celtic on 22 April 2015, coming on as an 81st-minute substitute in a Scottish Premiership match against Dundee.
He made one further first-team appearance that season, playing over an hour in a league match away at St Johnstone.
Tierney enjoyed a breakthrough season in 2015–16, appearing in over 30 matches and displacing the more experienced Emilio Izaguirre as first-choice left back.
For his performances he was awarded with both the Players' and Writers' Young Player annual awards, while Celtic also won the league title.
2016
Despite interest from Premier League clubs, Tierney signed a new five-year contract on 24 June 2016, keeping him at Parkhead until 2021.
After making his first appearances in the group stage of the UEFA Champions League, Tierney suffered ankle ligament damage during training on 27 October 2016 and was initially ruled out of action for two months.
During the layoff, which caused him to miss the League Cup Final, he received treatment on a recurring shoulder injury and attended several Celtic matches as a typical supporter in the company of his childhood friends.
2017
On 22 January 2017, after missing three months, he made his long-awaited return to the Celtic team in a Scottish Cup tie against Albion Rovers.
He suffered a jaw injury early in the 2017 Scottish Cup Final and had to be substituted for treatment.
Celtic won the match 2–1 to complete a domestic treble and undefeated season.
In spite of his lengthy injury absence, he featured in 40 matches during the campaign.
On 8 August 2017, Tierney was named as captain while also moving to central defender to command a back line of teenagers in a Scottish League Cup fixture against Kilmarnock; Celtic won the game 5–0, with Tierney providing an assist and scoring with a "wonderful strike" from 40 yards.
On 30 October, a week after scoring in an important league victory away to closest challengers Aberdeen, he extended his contract with Celtic until 2023.
By the end of the season, he had collected further personal accolades—winning both the Players' and Writers' Young Player awards for the third campaign in succession—and performed a major role in securing a historic 'double treble' for the club, making more than 50 appearances and playing the entirety of the domestic cup finals, both being 2–0 wins over Motherwell.
2018
Tierney played in Celtic's victory over Aberdeen in the 2018 Scottish League Cup Final on 2 December 2018.
2019
He joined Arsenal in August 2019 for a fee reported at £25 million, a record amount both for a Scottish national and for a player from the Scottish league.
Soon afterwards a hip injury meant that he was ruled out of action, returning on 24 February 2019.
He then suffered from a hernia, which subsequently required surgery.
On 8 August 2019, Tierney signed for Premier League club Arsenal, for a reported £25 million fee.
Tierney missed the early part of the 2019–20 season, having undergone a double hernia operation in May 2019.
He made his first-team debut for Arsenal in a 5–0 win against Nottingham Forest in the EFL Cup on 24 September.
Tierney assisted the first goal in a 4–0 home win against Standard Liège scored by Gabriel Martinelli a week later.
He made his first appearance in the Premier League on 27 October, in a 2–2 draw with Crystal Palace.
His season was further disrupted after suffering a dislocated shoulder in the game against West Ham United.
Tierney's impressive performances for Arsenal following the resumption of the Premier League after the COVID-19 pandemic saw him receive Arsenal's Player of the Month award for June.
He scored his first goal for Arsenal on 26 July, in a 3–2 win against Watford on the final day of the 2019–20 Premier League season.
2020
On 1 August 2020, Tierney was selected to start in the FA Cup Final against Chelsea, as Arsenal won their 14th FA Cup.
On 28 August 2020, Tierney was in the starting 11 in the 2020 FA Community Shield, which Arsenal clinched a 5–4 victory over Liverpool in the penalty shootout after the match was 1–1 after 90 minutes.
On 2 January 2021, Tierney scored the opening goal in a 4–0 away league win over West Bromwich Albion and later assisted the final goal, scored by Alexandre Lacazette.