As a young man, Anthony Joseph dreamed of becoming a rock star, not a critically acclaimed poet. In fact, had it not been for a box of papers he brought to the UK from Trinidad, where he grew up, the 46-year-old might never have come to write Sonnets for Albert, the collection that on Monday won him this year’s TS Eliot prize. In the early 90s, the poet spent three years as the lead singer of Zedd, a “four-piece heavy Black rock band”. Shortly after Zedd disbanded, Joseph was unwell and stuck at home when he rediscovered the box he had brought with him when he moved to the UK in 1989. It contained sheets of lyrics and poems he had written while living with his grandparents as a teenager. “I pulled this box out and I started looking through it, and I had a kind of epiphany,” he says. “I realised, ‘Damn man, this is what you are, you are actually a poet’. It was quite a profound moment. I started sort of shaping my life around poetry and just following it.” That’s not to say he stopped doing other things: Joseph continues to make music, blending spoken word and Trinidadian sounds in albums including Caribbean Roots and The Rich Are Only Defeated When Running for Their Lives. He has also written novels such as Kitch, a fictional biography of the calypso singer Lord Kitchener, which Colin Grant, in his Guardian review, praised for its prose “as tough as the world Kitch inhabited”. But Joseph is a poet at his core, he says, and arguably it is through his poetry that he takes on his toughest subjects: in Sonnets for Albert, he reckons with the absence of his father during his youth. “My dad has always been a muse to me,” he says. Because he wasn’t around when Joseph was a child, “he became this sort of almost mythological figure.” He remembers his father as being “very charismatic and very funny”, someone he would always look forward to seeing. “It would be sort of like this hero figure coming back out of the the desert.” When Joseph’s father died in 2017, he began to think of writing a selection of sonnets for him, and the result – after bending the form slightly to make the poems more musical – is Sonnets for Albert. As well as poems, the book also contains a number of photographs of Joseph’s father. “I tried to make sense of his absence by putting all the memories I have of him, as much as I could remember, as much as I could express, into a single collection,” Joseph says. “It doesn’t necessarily represent him,” he adds. “But it feels like he’s in the book in a permanent way now. So he’s no longer this absent figure in my life, he’s very present in the work for me.” Writing the poems was a way of “pulling [his father] into place”, he says, and trying to find “the capacity to love him”, which was “a difficult process, because he was not a great father”. It is a very personal collection, but there is power in being “brutally honest”, Joseph believes. “I talk about my father’s body and the feel of his chest, and these things are personal, but they’re also universal. Everyone has had that, or will have that feeling at some point.” As well as this universality, Joseph believes that Caribbean poets are “the historians and the biographers of people” from the area, because “so much of our history is lost and [has] been taken away from us”. “I also think that in a wider sense Caribbean life is at the centre of what it means to be human,” he says. “If anyone wants to learn about what it means to be a postmodern or postcolonial human being, look at the Caribbean. The Caribbean is a microcosm. Everything that you can see in the world – immigration, migration, climate change, issues around gender – you find it all compressed in the Caribbean.” Joseph is also an academic, lecturing in creative writing at King’s College London. Teaching means he has to keep reading contemporary work, he says, and recent favourites include Warsan Shire’s Bless the Daughter Raised by a Voice in Her Head and Fred D’Aguiar’s memoir Year of Plagues. He is currently working on a collection of essays, as well as a book of selected poems, and is due to record another album this year. Poetry, though, informs it all. “Over the years I have realised that being a poet means that you have a particular outlook, a particular way of looking at language and seeing the world in a language-based way,” he says. “You’re trying to find a new way every time of explaining what it means to be human.” Sonnets for Albert by Anthony Joseph is published by Bloomsbury (£9.99). To support the Guardian and Observer, order your copy at guardianbookshop.com.