The 27-year-old signed a three-year deal from Manchester United for a fee believed to be in the region of £12million and revealed that playing in Germany was a great attraction to him.
"I know with the English Premier League and the Primera Division in Spain two of the three major European leagues," Hernandez told Bayer's official website.
"Now I want to experience the Bundesliga.
"I have heard a lot of the great stadiums in Germany, where the fans are unique.
"The Bundesliga is set up extremely offensively, it is a great attraction for me.
"It's wonderful that I now get to play for a club like Leverkusen. Bayer is a great opportunity for me, I want to achieve something here."