Paraphrased from the Wikipedia entry (the smaller text):
"One for My Baby (and One More for the Road)" was written by Harold Arlen and Johnny Mercer for the musical The Sky's the Limit (1943) and first performed in the film by Fred Astaire. It was popularized by Frank Sinatra.
Harold Arlen described the song as "another typical Arlen tapeworm" - a "tapeworm" being the trade slang for any song which went over the conventional 32 bar length. He called it "a wandering song. Johnny (Mercer) took it and wrote it exactly the way it fell. Not only is it long - forty-eight bars - but it also changes key. Johnny made it work." In the opinion of Arlen's biographer, Edward Jablonski, the song is "musically inevitable, rhythmically insistent, and in that mood of 'metropolitan melancholic beauty' that writer John O'Hara finds in all of Arlen's music."
From Young at Heart (1954), this arrangement is very similar to the one used four years later on Frank Sinatra Sings for Only the Lonely:
Sinatra recorded the song several times during his career: In 1947 with Columbia Records, in 1958 for Frank Sinatra Sings for Only the Lonely, in 1962 for Sinatra & Sextet: Live in Paris, in 1966 for Sinatra at the Sands and finally, in 1993, for his Duets album. The latter, featuring Kenny G., closes the album and critics have noted that Sinatra almost seems to cry the final words "It's a long, long... man, it's long... road."
I'm afraid I don't know the specific year of this live Sinatra performance, but based upon his hair and the condition of his voice, I'd say it's just before he "retired" in June 1971. This is indicative of how, as he could rely less and less on his voice (particularly on ballads and softer songs), he became more and more of an actor and narrator of songs and interpreter of a lyric, most obviously on "One More for My Baby (and One More for the Road)":