The Egypt international completed his medical and put pen to paper after arriving in Turkey on Wednesday, when he received a raucous reception from supporters at Istanbul's Atatürk Airport before travelling on to Trabzon.
"Our new signing Mohamed Salah has signed the contract binding him to our club for two years, with the participation of our President Ertugrul Dogan," Trabzonspor said in a statement, before confirming the financial details on a public disclosure platform.
According to the club, Salah will receive a total guaranteed payment of €17m (£14.5m) per season, made up of a €10m (£8.5m) annual salary and a €7m (£6m) signing fee, along with performance-related bonuses.
The deal also includes a share of revenue from Salah-branded merchandise sold by the club's retail arm, put at 20 per cent in Trabzonspor's own disclosure, and an agency fee amounting to five per cent of his gross pay – though a similar commercial demand had reportedly contributed to the collapse of earlier talks with Beşiktaş.
Salah leaves Liverpool as a free agent after nine years at Anfield, where he scored 257 goals in 442 appearances and won the Premier League, Champions League, FA Cup and two League Cups among his honours, having announced his departure back in March.
He rejected interest from Saudi Arabia to join Trabzonspor, who finished third in the Turkish Süper Lig last season and will compete in the Europa League play-off round later this month.
"I am very happy to be in this incredible atmosphere. I don't recall ever seeing anything like this before," he said.
"There are 25,000 people here – it's incredible. I've never seen anything like it. I have achieved success everywhere I've been, and I want to achieve success at Trabzonspor as well."
An official unveiling was held at the club's Papara Park stadium, with supporters urged to wear their new-season kit "to witness history."