The liga outfit sacked Michel on Monday after one win in seven games which has left Los Rojiblancos languishing in mid-table.
But Emery insists that there is no need to bring in new players in January, as the squad at his disposal is strong enough to ensure the side climb back up the table.
“The team have the raw materials here, we cannot worry about someone important leaving, I am aware that this can happen, but I have been told that the sales will be kept to a minimum," he told reporters at his unveiling.
“I trust this team and the real stuff is here. I have every confidence in the club and the team.”
Emery was fired as coach of Spartak Moscow in November after losing 5-1 to Dynamo Moscow, and while he intended on taking a break, the Spaniard said Sevilla was an opportunity he could not turn down.
He continued: “My first thought after Russia was to take a holiday and relax, but you can't let an opportunity like this pass.
“Despite the situation, the atmosphere inside the club is very positive and I think it will help us pull this off."
Emery’s first game in charge will be a Copa del Rey tie away to Real Zaragoza on Wednesday night.