All Tennis Players How Many Grand Slams Has Boris Becker Won? Boris Franz Becker (German pronunciation: [ˈboːʁɪs ˈbɛkɐ], audio ; born 22 November 1967) is a German former world No. 1 tennis player.Boris Becker has won 6 Grand Slams. FacebookTwitterEmail How Many Grand Slams Has Madison Keys Won? How Many Grand Slams Has Jannik Sinner Won? How Many Majors Has John Isner Won?