Sen studied at St Columba's School and read literature at Hindu College, University of Delhi. As an Inlaks Scholar, he received a master's degree from the Graduate School of Journalism at Columbia University in New York City. Sen was an international poet-in-residence at the Scottish Poetry Library in Edinburgh, and a visiting scholar at Harvard University.
His books include Postcards from Bangladesh, Prayer Flag, Distracted Geographies, and Rain. He has edited anthologies including The HarperCollins Book of English Poetry by Indians (2011), World Literature Today Writing from Modern India (2010),The Literary Review Indian Poetry (2009) and Midnight's Grandchildren: Post-Independence English Poetry from India (2004). His work appears in anthologies such as Indian Love Poems (2005), New Writing 15 (2007), Language for a New Century: Contemporary Poetry from the Middle East, Asia and Beyond (2008) and Initiate: An Anthology of New Oxford Writing (2010).
Sen has been translated into other languages including Arabic, Bengali, Czech, Finnish, French, German, Greek, Hebrew, Hindi, Hungarian, Italian, Korean, Macedonian, Malayalam, Persian, Romanian, Slovenian, Spanish, Swedish and Turkish.
Sen's writings have appeared in newspapers, magazines, journals, and broadcast on radio and television. They include: the Times Literary Supplement, The Guardian, The Independent, The Financial Times, Poetry Review, Literary Review and the Harvard Review. He has broadcast on BBC World (TV), BBC Radio, PBS, Radio Tehran and Radio Jerusalem. He has written, edited and translated over 30 books and chapbooks.
Sen has directed or co-directed several short films and documentaries, including Rhythm, White Shoe Story, Woman of a Thousand Fires, Babylon is Dying: Diary of Third Street (nominated for a student Emmy Award), and Flying Home.
Sen received a Hawthornden Fellowship (UK) and was nominated for a Pushcart Prize (US) for poems included in Postmarked India: New & Selected Poems (HarperCollins). He won an A. K. Ramanujan Translation Award.
Sen is a member of The Plimpton Circle of The Paris Review, curator of the 'World Poetry Portfolio' series for Molossus, and serves on the editorial boards of The Literary Review, International Literary Quarterly, Orient Express and New Quest. In 2008 he was appointed director of the Delhi International Literary Festival. In 2010, he was the first foreign co-judge for the Arvon Foundation International Poetry Competition. He is the editorial director of Aark Arts publishers and editor of Atlas.