Although F# is its most well known early popularizer, it originated in Isabelle/ML, 1994, proposed by Tobias Nipkow.
Here is a blog post by Don Syme which embeds the email thread of its invention: https://web.archive.org/web/20190217164203/https://blogs.msd...
It's a fascinating look through time.
Of course, I should note this is the history for the pipe-forward operator for chaining (reverse) function application used in a programming language. The general concept is even earlier, as attested by the shell syntax for chaining anonymous pipes https://en.wikipedia.org/wiki/Pipeline_(Unix)#History.
Metanote: I was surprised I was unable to find an answer to who invented the (|>) pipe syntax through google. I could only find this Elm thread https://elixirforum.com/t/which-language-first-introduced-th... which got close but did not have the answer. I am therefore writing this here to hopefully surface it for future searches and "question answering AIs".