Goal broke the news of the club’s interest in the 25-year-old on May 9, with the explosive forward passing a medical on Thursday before finalising his switch to Anfield.
The Serie A club have disclosed the transfer is worth over £36 million, which could rise by another £7m due to add-ons, which would make him the Merseysiders' record signing.
Salah will earn in the region of £90,000 a week and takes over No. 11 from Roberto Firmino, who becomes the club’s No. 9.
The desire to see the Egypt international in a Liverpool shirt precedes this summer, with the Merseyside outfit failing in their attempts to recruit him from Basel at the turn of 2014 as Chelsea moved rapidly to snap him up instead.
His £12m switch to Stamford Bridge ultimately proved unsuccessful before loan spells followed at Fiorentina and Roma, the latter making the agreement permanent last August.
Salah proved a revelation at the Stadio Olimipico, contributing 19 goals and 12 assists across all competitions last season.
With manager Jurgen Klopp determined to add another intelligent, fluid and formidable player to his frontline, Liverpool would not miss out on the Egyptian again.
The Reds had an opening offer of £28m rebuffed by Roma at the start of June and persisted in negotiations despite the Giallorossi demanding over £40m at one stage.
Salah’s tirelessness, speed and decisiveness in the final third is perfect for the 50-year-old’s assertive blueprint and complements the attributes of an already accomplished attack.
He joins Dominic Solanke as an incomer ahead of 2017-18, with the Under-20 World Cup winner swapping Chelsea for Liverpool.
The talented teenager will officially link up with the Reds on July 1 following the expiration of his terms at Stamford Bridge.
A tribunal is expected to decide on how much training compensation Antonio Conte’s side will receive for the 19-year-old, with the clubs still a distance apart in their valuations.