Tarrant was raised in rural Tasmania, Australia. This was for all practical purposes a nineteenth century upbringing, without the use of wired electricity or indoor plumbing. His earliest influences included the Catholic Church and particularly the Latin Mass, Australian Aboriginal culture, and a passion for English literature, especially poetry. Tarrant was awarded a scholarship to attend the Australian National University, the premier Australian institution of higher learning, where he earned a dual degree in Human Sciences and English Literature.

Before and after his college experience, Tarrant worked at many jobs, ranging from working as a laborer in an open-pit mine, to commercial fishing the Great Barrier Reef. Eventually he also worked as a lobbyist for the Aboriginal land rights movement.

He was introduced to Buddhism in the Tibetan tradition but quickly found his spiritual home in Zen Buddhism. Tarrant moved to Hawaii to study Zen with the renowned social justice activist and Zen master, Robert Baker Aitken. He eventually became Aitken Roshi's first Dharma successor. At about this time he moved to California to complete his PhD in Psychology from the Saybrook Institute and where he established the California Diamond Sangha, which would eventually become the Pacific Zen Institute.

John Tarrant's reputation as a writer and poet grew with contributions to several publications, including among various journals the books Beneath a Single Moon: Buddhism in Contemporary American Poetry and What Book? Buddha Poems From Beat to Hiphop.

Tarrant's own books include his controversial book The Light Inside the Dark and the widely received Bring Me the Rhinoceros.

He has become one of the most interesting and creative of North American koan masters, through his many talks and essays published in periodicals and around the web, as well as through his book Bring Me the Rhinoceros: and Other Zen Koans To Bring You Joy.

Tarrent's Zen lineage comes through the Harada-Yastuni lineage of Zen whose root organization is called Sanbo Kyodan:

Daiun Sogaku Harada (13 Oct 1871-12 Dec 1961)

Hakuun Ryoko Yasutani (5 Jan 1885-28 Mar 1973)

Kyozo Koun Zenshin Yamada (Mar 1907-13 Sep 1989)

Robert Chotan Gyoun Aitken (19 Jun 1917-5 Aug 2010)

John Nanryu Ji'un-ken Tarrant (14 Aug 1949-)

Among Tarrant's Dharma heirs are:

David Weinstein located at PZI's Oakland Zendo branch site;

Joan Sutherland, head of the Open Source Network;

James Ishmael Ford, founder and senior teacher of the Boundless Way Zen network;

Daniel Terragno, of Rocks and Clouds Zendo.

One popular quotation, which signifies Tarrant's contribution to Western Zen is:

"What is the mind like if it’s not occupied with plans and schemes, and fears that the plans and schemes will fail? What if your unexamined beliefs were to fall away and you were to live without them, and also to live without the thought that you had given anything up?"