The novel, Lynch's fifth, seeks to show the unrest in Western democracies and their indifference towards disasters such as the implosion of Syria.
"From that first knock at the door, Prophet Song forces us out of our complacency as we follow the terrifying plight of a woman seeking to protect her family in an Ireland descending into totalitarianism," Esi Edugyan, chair of the Booker's 2023 judges, said on Sunday.
"This is a triumph of emotional storytelling, bracing and brave."
Lynch, who was previously the chief film critic of Ireland’s Sunday Tribune newspaper, said he wanted readers to understand totalitarianism by heightening the dystopia with the intense realism of his writing.
"I wanted to deepen the reader's immersion to such a degree that by the end of the book, they would not just know, but feel this problem for themselves," Lynch said in comments published on the Booker Prize website.
Lynch became the fifth Irish author to win the Booker Prize, after Iris Murdoch, John Banville, Roddy Doyle and Anne Enright, the organisers of the competition said.
The Northern Irish writer Anna Burns won in 2018.
Past winners of the Booker, which was first awarded in 1969 include Margaret Atwood, Salman Rushdie and Yann Martel.
Prophet Song is published in the UK by Oneworld which also won the prize in 2015 and 2016 with Marlon James’s A Brief History of Seven Killings and Paul Beatty’s The Sellout.
