The 59-year-old has coached all three of Portugal's biggest teams, Porto, Benfica and Sporting Lisbon in a distinguished managerial career spanning four decades.
Santos has also enjoyed success in Greek football with AEK Athens, Panathinaikos and PAOK before replacing Otto Rehhagel as Greece coach in July 2010.
Greece made it through the group stages at Euro 2012 and this year's World Cup under Santos' tutelage, before respective eliminations at the hands of Germany and Costa Rica.
Santos was sent to the stands during the Costa Rica defeat and currently has an eight-game FIFA ban hanging over him, which could render him unable to lead Portugal from the touchline until their final Euro 2016 qualifier in Serbia next year.
Portugal suffered a disastrous World Cup campaign.
Cristiano Ronaldo dragged them into the tournament via the play-offs, but the Real Madrid star's lack of fitness was evident in Brazil and the Iberian nation went out at the group stage.
A 1-0 defeat to Albania in their opening Euro 2016 qualifier proved to be too much for Bento, who stepped down afterwards.
Bento's reign will begin with trips to France and Denmark next month, though no indication over his availability to lead the side in them has been given.
