No, I wasn’t around in 1965, but I absolutely remember this song from when I was a tot in the late 1970’s. My parents played it quite a bit; they had a few Frank Sinatra albums among their stacks of 8-track tapes in the living room entertainment center. I wasn’t supposed to touch them, but I did. (Hey, they were right at the bottom level, where I could fiddle with them. And, as a kid, would read anything — even album titles.)
Anyway, this Internet thingamajig tells me that the song was written in 1961 by Ervine Drake for the Kingston Trio. Sinatra won a Grammy in 1966 for his rendition of it, as did Gordon Jenkins for his accompanying instrumental work.