There were two distinct chapters to Sean Hughes’ career: the comedy prodigy and ubiquitous TV star, then – after a period of silence – the rumpled refusenik, a celebrity opt-out ploughing an ever grouchier (but just as funny) furrow along standup’s margins. Not many comics run away from commercial success, but at the turn of the century Hughes quit standup for several years. “I found myself playing 4,000-seater venues packed with 14-year-old girls screaming at me,” he said. “That wasn’t why I did comedy.”

For Hughes – at least after his early years, when he admitted he was motivated by fame – standup was always the space he sought to speak the truth in all its messy complexity. After his career hiatus, he returned with knotty, almost wilfully uningratiating shows, which didn’t always cohere, but which throbbed with grumpy-gadfly personality and showed bright flashes of the talent that once made him the youngest ever winner of the Edinburgh Comedy award (known back then as the Perrier).

I always bracketed him in my mind with fellow Irishman Dylan Moran, who bagged a Perrier a few years later. But really, Hughes didn’t belong in anyone’s club. He gave every impression of being a cussed character and committed loner, one of those who ended up in comedy (or at least, stayed there) not because it was cool, but because his misfit character and the misery of his upbringing qualified him more for standup than for anything else. In interviews and on stage, he discussed his father’s alcoholism. His childhood was also marked by moving from London to Dublin: “I got a lot of stick, like, ‘Shut up, you Brit,’ and I felt like an outsider from very early on.”

‘He worked slyly to challenge comforting bromides’ … Hughes at Edinburgh festival fringe in 2012. Photograph: Murdo Macleod for the Guardian

Because the jaunty misanthropy of his middle-age suited him so well, it’s hard to remember him young. But his Channel 4 sitcom Sean’s Show – detailing the everyday misadventures of bumbling Hughes, and addressed from his fictional flat directly at his studio audience – was ahead of its time. Now, it can be seen as an early staging post (after It’s Garry Shandling’s Show, before Spaced) in the development of the meta-sitcom.

I didn’t start watching his standup till the second chapter of Hughes’ career, when he returned from his self-imposed exile to deliver a series of curmudgeonly bulletins from uncompromising and unheralded middle age. Sometimes, this was stock standup fare about the indignities of getting old. More often, it suggested deeper and darker currents swirling below the comedy’s surface. He complained that his audience were all his age, and no one heckled him any more. He was never a shock merchant, but the best of his standup worked slyly to challenge comforting bromides, to raise disagreements and unease. Such was the case with a set about his father’s death, Life Becomes Noises, that was pretty ruthless in its lack of sentimentality.

In one show, I remember him taking impish pleasure in a joke that mocked Stephen Fry – then at the peak of his national-treasure popularity. His audience resisted – as they often did at his jokes about his own mental health and vegetarianism, which cheerfully refused to observe the pieties attendant on either. With Hughes, there was never any sense of provocation for the sake of it. Whether he was being mildly or monstrously funny, you seldom doubted that he was saying what he found, with neither fear nor favour. “I just wanted to tell the truth,” he said of his comedy career, “and be listened to.” So he did, so he was – and it’s poignant to think that we can’t listen any longer.