The Egyptian signed from Roma in the summer of 2017 and went on to have one of the most memorable debut Premier League seasons in history, scoring 32 goals in the competition.
Salah had some experience in England from his ill-fated spell with Chelsea. And speaking to the club's website, the 25-year-old said he had always dreamed of a move to England, but specifically with the Reds.
"The story of me playing as them on my PlayStation is true; sometimes it was as other teams, but most of the time I was Liverpool," said Salah.
"Back then, I could never have imagined I'd be here one day, but it was always a dream of mine and you have to try and follow them.
"When there was interest again last year, I was very interested in coming to Liverpool straight away in my head, but you also have to see what the plan for you is and how you will fit into it."