The Barcelona-born coach, who also acts as a scout for the national Spanish Federation, has been handed the role in South Wales following the departure of Adrian Tucker.
"I'm delighted to be given the opportunity to work at a club that is growing at a rapid rate in the best league in the world," Garcia told the club's official website. "All the information I've received about the city and how the club, chairman and manager work convinced me to come to Swansea.
"It was hard to leave Sevilla because it is such a good club with good people, but it's a great opportunity for me to work in such a positive environment where I can develop and grow with the club. It's an exciting challenge."
Garcia spent three years working with Sevilla's senior team.