Alexander-Arnold is a graduate of the Liverpool Academy, and made his senior debut in 2016, aged 18.
He has since made over 40 appearances and won the club's Young Player of the Season award in 2017 and 2018.
He represented England at all youth levels from before making his senior debut in June 2018.
He was also called up for the Russia 2018 World Cup at the age of 19.
Alexander-Arnold was born in West Derby, a suburb in the English city of Liverpool.
He attended St Matthew's Catholic Primary School and it was at community summer camp that his school was invited to, where Liverpool first spotted his talents at the age of six, and the academy coach Ian Barrigan offered him the chance of joining the Liverpool Academy.
He has been at Liverpool ever since, captaining the U16 and U18 level under coach Pepijn Lijnders.
As a youngster, he caught the eye of everyone at Liverpool, and club legend Steven Gerrard even gave a special mention to Alexander-Arnold in his autobiography.
"Trent Arnold has a terrific chance of making it as a top professional,” said Gerrard.
Alexander-Arnold celebrates scoring a Liverpool goal
Alexander-Arnold got his first major breakthrough in the summer before the 2015-16 season, as he was selected by manager Brendan Rodgers for Liverpool in a pre-season 2-1 friendly win against Swindon Town.
 Alexander-Arnold made his first competitive debut on 25 October 2016, starting in a 2–1 victory over Tottenham Hotspur in the fourth round of the EFL Cup.
Although he was booked in the first half and replaced in the second half, Liverpool manager Jürgen Klopp saw enough in him to slowly embed him into the first team squad.
On 8 November 2016, Liverpool announced that Alexander-Arnold, along with, had signed new long-term contracts with the club.
 Later that month, he started in Liverpool's next EFL Cup match against Leeds United.
Liverpool won 2-0 and Alexander-Arnold was named man of the match after setting up Divock Origi sealed a sterling performance for the promising youngster.
Sky Sports pundit and former Liverpool right-back Jamie Carragher enthused after the game that he believe that performance alone vindicated Jurgen Klopp's decision to start the season with only one recognised right-back.
"He just looks like a fantastic athlete, perfect for the full-back position.
He’s only 18 so you think about how he’s going to look physically in three or four years’ time," said Carragher.
On 14 December, Alexander-Arnold then made his Premier League, coming on as a late substitute for Origi in a 3–0 win over Middlesbrough, and then just over a month later on 15 January 2017 he made his first league start in a 1–1 draw with Manchester United.
 By the season's close, Alexander Arnold had cemented his place in the first team squad after making 12 appearances in all competitions, and was even rewarded by winning Liverpool's Young Player of the Season 2016-17.
During that summer, Alexander-Arnold signed a new long-term contract with Liverpool.
 On 15 August 2017, he scored his first goal for Liverpool in a 2-1 win against 1899 Hoffenheim in the Champions League.
The record equalling final score: 7-0 to Liverpool was the biggest ever away win in a European competition by any English side.
He then scored his first Premier League goal for Liverpool on Boxing Day, netting a second-half goal in the 5–0 demolition of Swansea City at Anfield.
 On 4 April 2018, Alexander-Arnold became the youngest English player to start in a Champions League quarter-final.
It was a perfect performance for Alexander-Arnold as he helped Liverpool hammer Premier League rivals Manchester City 3-0, and after the game he was named man of the match on what was the biggest stage of his short career to date.
On 10 May, he was awarded when he won the Liverpool Young Player of the Season award for the second season running.
 Later that month, he became the youngest Liverpool player in a Champions League Final when he was named in the starting line-up to play against reigning champions Real Madrid.
He fared well, but Liverpool lost 3-1 after two glaring mistakes by goalkeeper Loris Karius gifted Real Madrid the title.
England Youth Teams
On 24 March 2017, he scored twice in a 3-0 for England U19 against Spain U19.
The win sealed qualification for the U19s for the 2017 UEFA European Under-19 Championship.
 Although he was an integral part of the team that qualified for the championships in Georgia later that year, Alexander-Arnold wasn't selected as Liverpool had an agreement with the FA to rest him that summer.
 England went on to win the tournament, beating Portugal 2-1 in the final to claim their first ever title in the competition.
England national team
In March 2018, while part of the U21 team, Alexander-Arnold was invited to train with the England senior squad.
He was added to the ranks to bolster the squad for friendlies against Netherlands and Italy,  but he wasn't selected for the matches.
In May 2018, he was sensationally selected for England's first team squad for Russia 2018.
 It was his just rewards for his sensational rise.
His debut followed on 7 June 2018 when he was picked to start in the 2-0 World Cup warm-up win against Costa Rica at Elland Road, Leeds.
Better was to come in just his second appearance as he was handed his competitive debut in the World Cup Group G against Belgium. England lost the game 1-0, but Alexandar-Arnold, who became only the fourth teenager to start a World Cup match for England, won the man of the match award.
 It was his only performance as England progressed through the World Cup to the semi-finals, where they were beaten by Croatia 2-1 after extra time.