Lightfoot composed the song in 1964, but the genesis of the song took root during his sojourn in Westlake, Los Angeles during 1960. During this time Lightfoot became homesick and used to go out to the Los Angeles airport on rainy days to watch the approach of the aircraft  The imagery of the flights taking off into the overcast sky was still with him when in 1964, about five years later he was baby sitting his 5 month old baby son and he thought “I’ll put him over here in his crib, and I’ll write myself a tune.” "Early Morning Rain" was the result.
The Canadian husband and wife duo Ian & Sylvia were the first artists to release this song in 1965, though the version by Peter, Paul & Mary was the most commercially successful version. There was over a year's time lag between their recording and Lightfoot's recording and its release in 1966. The Grateful Dead also recorded the song in 1965. Funk super-group Cameo frequently performs the song live as an homage to Lightfoot's influence on the band.We Five released a version of the song on their 1970 album, Catch the Wind.