Jack Kerouac (1922-69), the King of the Beats, started writing haiku with the belief that this short poetic form was an avatar of Zen, and he pursued both haiku and Zen to his drunken end.
I don't know if this is common knowledge among those who continue to be enthralled by "On the Road," published more than 45 years ago, but it is what comes through in the generous collection of more than 700 of his haiku assembled by Regina Heinreich in "Jack Kerouac: Book of Haikus." (Yes, as Weinreich notes, Kerouac added "s" to the word "haiku" to indicate plural, which is seldom done today.)
Among the earliest Japanese advocates of the notion that haiku embodies Zen was Mastuo Basho's contemporary Onitsura (1661-1738). Among the most famous in recent years is Nagata Koi (1900-97). Onitsura regarded "Teizen ni shiroku saitaru tsubaki kana (In the garden blooming white are camellias)" as his signature piece. It was a response to a Zen master's query: "What's your haikai eye like?"