Autumn Leaves is played often in two different keys, G minor and E minor. However, when I was researching this tune we found very few recordings in E minor. The recordings we checked out were in all kinds of different keys. Nevertheless, G minor and E minor are considered the standard keys for this tune.
Also worthy of note, this standard was first written in 1945 in France under the name “Les Feuilles Mortes,” which is translated “the dead leaves” or “fallen leaves.” Though not technically a part of the Great American Songbook due to the nationality of the tune’s composer, the tune eventually came to have all of the characteristics of other songs in that category after Johnny Mercer wrote English lyrics in 1947, save for the fact that it was not composed by an American.
This tune is difficult to categorize, and we recognize that the Great American Songbook isn’t a perfect category for the tune. However, the tune fits even less neatly into all of our other categories. It is by default that we put put the tune into the Great American Songbook category because it shares so many characteristics with the other songs in that category, such as frequent ii-V-Is, traditional harmony, lyrics, and a singable melody.