Political leaders in Northern Ireland have led tributes to the writer and former Guardian and Observer correspondent Henry McDonald, who has died at the age of 57. Family, friends and media colleagues expressed shock and sadness on Sunday after McDonald died at the Royal Victoria hospital in Belfast, where he was being treated for cancer. McDonald was the Ireland correspondent for the Guardian and Observer over a 23-year span before becoming the Belfast News Letter’s political editor in 2022. He wrote landmark books on the Troubles and was renowned for his insights into paramilitaries, the security services and politics. Jeffrey Donaldson, the Democratic Unionist party (DUP) leader, said McDonald was one of the most knowledgable commentators on Northern Ireland politics. “Always enjoyed my conversations with a man who was good humoured, insightful & passionate about this place,” he tweeted. Naomi Long, the Alliance leader, said McDonald was tenacious, perceptive and had a quick wit. “He will be desperately missed. Thoughts with all his family and friends, grieving his loss,” she said. Doug Beattie, the Ulster Unionist party leader, called McDonald a fantastic author, journalist and friend. McDonald, a father-of-three, learned in 2018 that he had stomach cancer and a serious heart condition. He was treated for both. But last year developed sepsis, then the cancer returned. Ben Lowry, the News Letter’s editor, said staff were distraught at losing a much-loved colleague who died far too young. “From his very first day here he was bursting with ideas and stories. Henry’s death leaves a major hole in the paper, and all the staff send their deepest sympathies to his family,” he said. Noel Doran, editor of the Irish News, where McDonald started his career, said he was a talented writer and one of the great characters of Belfast journalism. Ben Quinn, a Guardian reporter who worked with McDonald, called him one of the paper’s greats. Suzanne Breen, the Belfast Telegraph’s political editor, hailed his curiosity and integrity. “His breadth of knowledge was breathtaking. They don’t make many like that nowadays,” she said. McDonald’s passion for scoops was matched by his fervour for two football teams – Premier League Everton and Cliftonville of the Irish League’s top division. Their victories on 4 February – along with wins for Hibernian in Scotland and Ireland’s rugby union team – were the subject of his last tweet: “The stars aligned to cheer me up today.” He also had a lifelong love of punk music, a theme in his coming-of-age novel, Two Souls, published in 2019. He was working on a new novel that fused the first world war with a contemporary ghost story. McDonald grew up in the nationalist Market area of Belfast in the 1970s when the Troubles were at their height. The day a loyalist car bomb exploded outside his home featured in a 2018 article with a memorable opening line: “When I was blown up I was watching It’s a Knockout.” The son of a dressmaker and a labourer, McDonald attended St Malachy’s College grammar school and read philosophy at Queen’s University Belfast, before studying journalism in Dublin. He covered the first Gulf war for the Irish News, which led to him writing a book about Irish peacekeepers in Lebanon. After returning to Northern Ireland, he wrote and co-wrote books about loyalist paramilitaries, the Ulster Unionist leader David Trimble and Sinn Féin’s Martin McGuinness. Despite an ostensibly nationalist background, McDonald applied unsparing scrutiny to Sinn Féin and the IRA before and after the 1998 Good Friday agreement. McDonald is survived by his sister Cathy, his children Lauren, Ellen and Patrick, and his partner, Charlotte Blease.