Soft-spoken and often spoofed for overusing 'tranquility' to describe his team's mood, Bento staged a remarkable revival.
Taking over from Carlos Queiroz, in September, 2010, when Portugal were second to last in Group H after taking one point from their first two games, a 4-4 draw with Cyprus and a 1-0 defeat to Norway, he led them to a memorable 6-2 aggregate play-off win over Bosnia and a place in the finals.
At first, Bento's appointment raised a few eyebrows.
As Sporting coach he failed to win a league title, winning four domestic cup competitions over a six-year period. Fans were also disappointed when Real Madrid's Mourinho, who said he was available to coach Portugal for a brief period, pulled out.
Bento was seen as disciplined and rigorous, but his coaching style was regarded as over-defensive and unattractive while at the Lisbon club.
But, in the Portugal hot seat, he has thrived.
The 42-year-old former international holding midfielder successfully rallied a demoralised team to achieve instant success, becoming the youngest coach to guide Portugal to a major tournament. He was also the first to win his first five matches.
Portugal were transformed into a more tactically-aware and pragmatic team, with Bento unleashing the potential of key players Cristiano Ronaldo and Nani.
His fallouts with Ricardo Carvalho and Jose Bosingwa, who dropped out, threatened an upset, but he retained control of the dressing room and maintained high levels of motivation.
Bento said he is not bossy and often consults players when making decisions.
"Why wouldn't I discuss (tactics) with the players? Obviously I won't let them choose if we play 4-3-3 or 4-4-2, but we can say that the dish is steak and then ask them if they want it well-done or medium rare, with rice or with a little pasta on the side," Bento, who worked as a waiter in his parent's restaurant during his youth, told Expresso newspaper.
"I help prepare (the tactics), the players execute," he said.
Bento played with the great Claudio Caniggia during his spell in Benfica between 1994 and 1996 and served at Sporting for 10 years, first as a player and then as a coach.
Euro 2000 was both one of the highest and lowest points of his career.
In a memorable campaign, he helped steer Portugal to the semi-finals where they were eventually knocked out by France, a match that saw Bento lose his cool over the refereeing decision that awarded that year's European champions a decisive penalty.
Bento received a six-month ban for shouting at the referee and trying to take the red card from the official's hand as he showed it to Nuno Gomes for dissent.