The mellifluous baritone was compared to a down comforter, or a slow drip of midwestern molasses or your grandfather telling a bedtime story, a voice millions of Americans grew up with.

Garrison Keillor told strange, funny, idiosyncratic tales of small-town America in A Prairie Home Companion, a homespun variety show which over four decades reshaped public radio and made its host a household name.

Keillor sang, performed skits and ended each show with a monologue about his fictional hometown, Lake Wobegon, “where all the women are strong, all the men are good-looking and all the children are above-average”, weekly broadcasts which made listeners feel they knew him.

They didn’t. Off stage, away from the mic, Keillor was shy, melancholy and distant. He avoided eye contact and didn’t much like talking about himself, or talking at all. His shows reflected his fascinations, not his inner life. “It was never about self-expression, never,” he told the New York Times last year.

On Wednesday a shard from his private life punctured the enigma. Minnesota Public Radio (MPR) fired Keillor, 75, over allegations of “inappropriate behavior with an individual who worked with him”.

The allegations related to his conduct while making A Prairie Home Companion, leaving the network “saddened”, its president, Jon McTaggart, said in a statement. “We believe this decision is the right thing to do and is necessary to continue to earn the trust of our audiences, employees and supporters of our public service.”

MPR said it learned of the allegation last month and contracted an outside law firm to investigate, which it continues to do.

Of all the recent sexual misconduct cases this is one of the most incongruous and discordant. The tall, stooped broadcaster is not only respected but beloved, a seeming emissary from a kinder, gentler America who criss-crossed the nation recording shows with audiences who joined him in singing hymns, pop ballads and the national anthem.

“They’re singing it a cappella, there’s no band playing. It’s just people’s voices around you, in the dark,” he told the Guardian in 2015. “The point of all this – so obvious that you don’t even need to point it out – is that we are one country, and this is the basis of everything.”

But now this voice from a semi-rural and mythical America between the coasts joins Harvey Weinstein, Brett Ratner, Donald Trump, Matt Lauer, Al Franken and other prominent figures accused of wrongdoing.

In a statement Keillor expressed gratitude for a long, rich career. He sounded wistful. “I’ve been fired over a story that I think is more interesting and more complicated than the version MPR heard. Most stories are. It’s some sort of poetic irony to be knocked off the air by a story, having told so many of them myself, but I’m 75 and don’t have any interest in arguing about this. And I cannot in conscience bring danger to a great organization I’ve worked hard for since 1969.”

He told a local newspaper he had been accused of inappropriate touching. “I put my hand on a woman’s bare back. I meant to pat her back after she told me about her unhappiness and her shirt was open and my hand went up it about six inches. She recoiled. I apologized. I sent her an email of apology later and she replied that she had forgiven me and not to think about it. We were friends. We continued to be friendly right up until her lawyer called.”

Garrison Keillor with Meryl Streep and Lindsay Lohan in Robert Altman’s big screen take on A Prairie Home Companion. Photograph: AP

Until full details of the case emerge the impact on Keillor’s legacy remains unclear. Keillor, an avowed Democrat who loathed Donald Trump, retired from A Prairie Home Companion last year but remained a familiar presence through repeats and on another show, The Writer’s Almanac, which featured poetry and historic tidbits. MPR said it would drop the repeats and the Almanac.

Keillor is woven into US culture. The author of dozens of books – essays, poetry, novels – he has appeared or been referenced in Saturday Night Live, Doonesbury, Family Guy and The Simpsons (Homer, not getting the humour in a Keillor-esque monologue, bangs the TV and yells: “Be more funny”).

Keillor grew up in Anoka, Minnesota, the third of six children, to parents who were part of the Plymouth Brethren, a fundamentalist Christian sect that forbade dancing and cinema outings. He wrote for the local paper, majored in English in college and started in radio in 1969 as a classical music announcer.

The New Yorker magazine published one of his short stories, which led to a journalistic assignment in Nashville in 1974 covering the Grand Ole Opry, a country music event which inspired the young writer to create a variety show that became A Prairie Home Companion.

Its popularity peaked a decade ago, with 4.1 million listeners. Detractors found Keillor’s style syrupy and affected but colleagues like Ira Glass called it richly emotional and contemporary, by turns quirky, heartbreaking and funny.

Keillor, married three times, once called marriage the “deathbed of romance”.

Katy Sewall, 40, a Seattle-based public radio producer who considers Keillor a friend and mentor, expressed hope his work would endure. “He has done so many amazing things. It would be terribly sad if this tarnished what he’s done. He gave dignity and high profile to people who live in small towns. He had this earnest sweetness. A very sweet, very calm voice with a slight whistle.”

Sewall spent a month in 2009 living with Keillor and his family at their Minnesota home while working on A Prairie Home Companion. “He was always extremely respectful. I never once felt anything remotely creepy. He almost became a fatherly-type figure.”

A day before his firing the Washington Post published a column by Keillor which ridiculed demands for Franken, the Democratic senator, to resign over groping claims. “This is pure absurdity, and the atrocity it leads to is a code of public deadliness.”

A woebegone lament from an author who, it turns out, may have been anticipating his own professional obituary.