John Clayton Mayer (born October 16, 1977) is an American singer-songwriter, guitarist, and producer who dated Taylor Swift from December 2009 - February 2010. The two had worked together on the song "Half of My Heart" for his 2009 album Battle Studies. Taylor's song off of her 2010 album Speak Now, "Dear John", is very likely about him, but was never confirmed by Swift.
Mayer, who was born in Bridgeport, Connecticut, released his first album, Room for Squares, in 2001 and has achieved success since then with such hits as "Your Body is A Wonderland", "Daughters", and "Gravity". He has won 7 Grammy Awards.
His last album, The Search for Everything, was released on April 14, 2017. He is now working on a new album.
Mayer has become notorious for his personal life, which has attracted tabloid attention. In addition to having dated Taylor, Mayer has also dated such stars as Jessica Simpson, Jennifer Aniston, Cameron Diaz, and Minka Kelly. He's also openly discussed his private life with the media. Mayer was in an on-off relationship with Taylor's ex-enemy, singer-songwriter Katy Perry, which has attracted tabloid headlines. The two worked together on the song "Who You Love" for his album, Paradise Valley.
Some suspect that Mayer may have been part of the reason why Taylor and Katy were feuding.