16 January 2024 08:00 pm Views - 146
Mourinho, 60, took over in May 2021 and led Roma to the Europa Conference League title a year later and the Europa League final in 2023.
But they are ninth in Serie A, five points off the Champions League places, and last week were knocked out of the Coppa Italia by city rivals Lazio.
Former midfielder De Rossi will replace Mourinho until the end of the season.
The club legend, 40, came through Roma's academy and played 616 times for the first team between 2001 and 2019.
De Rossi retired in 2020 and has since had one spell as manager - a 17-game tenure at Serie B club SPAL which ended with the Italian's sacking last February.
"We believe that the leadership and ambition that have always characterised him can be decisive in chasing the objectives that the team has ahead of it until end of the season," said Roma's owners Dan and Ryan Friedkin.
"We knew the indissoluble bond that unites Daniele to the club, but the enthusiasm with which he immediately accepted this challenge... further convinced us of his ability to be a guide for the players and a proud representative of the values of this club."
De Rossi, who played 117 times for Italy and won the World Cup in 2006, said: "The emotion of being able to sit on our bench is indescribable, everyone knows what Roma is for me, but the work that awaits all of us has already taken over.
"We have no time, no choice. Being competitive, fighting for our goals and trying to achieve them are the only priorities that my staff and I have given ourselves."
De Rossi's appointment came just four hours after the sacking of Mourinho, when the Friedkins thanked the Portuguese "for the passion and commitment he has shown" as manager.
"We will always have great memories of his stewardship, but we believe that, in the best interests of the club, immediate change is necessary," they added in a statement.
Mourinho received a second successive red card in the Lazio loss and afterwards compared himself to Harry Potter, suggesting his profile was "raising expectations" for what Roma could achieve.
That result was followed by a 3-1 league defeat by AC Milan on Sunday, which left Roma five points adrift of fourth-placed Fiorentina and led to his dismissal.
Victory in the 2022 Conference League secured Roma's first major European title and earned Mourinho huge support among the club's fanbase.
But after they were beaten on penalties by Sevilla in last season's Europa League final Roma made a poor start to the current campaign, taking just five points from their first six Serie A matches.
With Roma 16th in the table, the former Manchester United, Chelsea, Real Madrid and Tottenham boss said he had rejected the "craziest offer" to leave last summer.
Mourinho's contract was due to expire at the end of the current season.