Interest from Barcelona and PSG has been scorned with the 24-year-old signing a contract that makes him the highest paid at Liverpool.
Coutinho believes Liverpool are going to get better and his dreams will be fulfilled with Jurgen Klopp in charge.
He told their official website: “I am very happy to sign a new contract for this club. It is a club that I am very grateful to and this shows my happiness here.
“I will work much harder to repay the belief shown in me.
“This is a fantastic club, one of the biggest clubs in the world – and we should be there amongst the other big clubs. This is a football club with great players and great technical staff. It has everything to achieve great things in future.
“Since we [his family] arrived here we were welcomed with open arms by everyone.
“We feel at home in this city, we feel a part of this city. It is a very important day for me, my wife and my daughter. I am happy – and everyone is happy at home!”
And his ambition now is to help fire the Reds to silverware. “Titles, I think that is very important,” he said when asked about his targets over the course of his new deal.
“When I say titles, I mean leagues – and this is one of the best leagues in the world – but also the Champions League and fighting with the best teams in Europe.
“That is my aim – it is the aim of everyone at this football club to be up there. Every player, every staff member at this club. This is what we are searching for.”