Donovan, 27, who has scored 42 goals in 120 appearances for the U.S., was handed the No. 9 shirt for the rest of the season when he was unveiled at a news conference ahead of Everton's Premier League match at Arsenal on Saturday.
"It is not just about coming in for a few months and having a kick-about," he said.
"This is the middle of the season, they have a few injuries and need immediate help so I have to be ready and that helped me prepare.
"The reality is I'm here to do a job and help the team win. I'm not just here to have fun for a few months. What I'm good at is creating chances and that is what I'll try to do here."
Donovan said his Galaxy team-mate David Beckham, who is on loan at AC Milan during the Major League Soccer close season, advised him to make the move after Everton, who are 12th in the 20-team standings, showed interest in him.
"David and I speak a lot and he is confident I will do fine," he said.
"Knowing him, being around him and playing with him I can see what it takes to make it at a place like this and if you are not ready and prepared you can get passed by."
Donovan is expected to play an important role for his country at this year's World Cup finals in South Africa and will link up at Everton with U.S. goalkeeper Tim Howard.
