How many times tennis majors champions played in the qualifiers round?

No qualifier to one of the four major championships singles main draw has ever won that year's tournament. The farthest a qualifier has reached at a major is the semifinals with John McEnroe reaching the 1977 Wimbledon Semifinals as a qualifier. Other qualifiers to reach grand slam semifinals are Filip Dewulf at the 1997 French Open and Vladimir Voltchkov at the 2000 Wimbledon Championships. A wild card though has won a major before with Goran Ivanišević winning the 2001 Wimbledon Championships as a wild card. On the women's side Alexandra Stevenson made the semis at Wimbledon in 1999 as a qualifier.