The 25-year-old has put pen to paper on a four-year contract with the Gelsenkirchen-based club and will make the short move across North Rhine-Westphalia on 1 July 2014.
'Delighted he's chosen the Royal Blues'
"Sidney Sam has not only proven how big an influence he can have in attack with his strong performances this season," said Schalke's sporting director Horst Heldt. "He's also shown he can play in a variety of positions. He's very ambitious and would like to be very successful with Schalke."
"We're really delighted that he's chosen to join the Royal Blues," added Heldt from Schalke's training camp in Doha. Sam, formerly of Bundesliga 2 side 1. FC Kaiserslautern, last played on November 23, when he pulled muscle fibres in Leverkusen's 1-0 win at Hertha Berlin. He has scored a total of seven goals in the Bundesliga this season in just 13 appearances.
Alongside and South Korean , Sam has formed part of a fearsome trio which has spearheaded Leverkusen's rise to second in the table at the midway stage of the season. Between them, they have struck 23 of Leverkusen's 32 goals so far this season.
Sam has also been capped five times by Germany and is a serious contender for the 2014 FIFA World Cup squad in Brazil, although he is currently working his way back from injury.