Elliott became the youngest player to feature in England’s top flight aged 16 years and 30 days in May 2019 after coming on as a substitute in Fulham’s 1-0 loss away to Wolverhampton Wanderers.
Following the Cottagers’ relegation to the second tier of English football, Elliott failed to agree terms on a new contract, and Liverpool moved swiftly to snatch the highly-rated winger from the clutches of Arsenal, Real Madrid, Paris Saint Germain and Manchester City, who were all keeping tabs on the youngster.
Elliott was still ineligible to pen professional terms due to his young age after moving to Anfield but has now done so after recently celebrating his 17th birthday.
"I think since the first day I've walked in, it's been an indescribable journey so far," Elliott told Liverpool's official website.
"I think now to top it off with my first professional contract is a dream come true for me and my family.
"I'm excited to see what the future holds and I'm just excited to give everything to the club and the fans."
Liverpool manager Jurgen Klopp added: “Brilliant news – [I’m] really happy. Harvey is such an exciting prospect. I love his attitude, enthusiasm, bravery – love he has the right amount of football confidence and cheekiness.
“The public maybe doesn’t know the real Harvey yet and part of that is because we have looked to shield and protect him. But he is such a nice, polite, humble boy who is appreciative of the talent and opportunity he has – and just loves football. He loves the game first and foremost, would play every minute of every day if he could – and he loves this club also and that’s a nice mixture.
“What is critical and so important is that he is given time and space to develop.”
Elliott has made eight appearances in all competitions for Liverpool this season, including two in the Premier League.