Media tycoon Pierre Karl Péladeau has quit as leader of Quebec’s main separatist party after less than a year in charge, ending a major soap opera in the province’s political history.

Mr. Péladeau said he had to choose between his family and politics – and he chose his family.

“I see no alternative,” he said on Monday afternoon. “I was forced to make a heartbreaking decision between my family and my political project – our political project.”

Mr. Péladeau was hailed as a business-savvy and get-it-done leader when he took the helm of the Parti Québécois. His brief political career was built on the popularity he shared with long-time companion and star television producer Julie Snyder. Together, they were a power couple in Quebec’s entertainment and media scene.

His political life ended on Monday with his marriage falling apart in a most public way and the party languishing with the same historically low levels of support it had in the 2014 election.

Through his political career Mr. Péladeau remained the controlling shareholder of media and telecom company Quebecor Inc. On Monday, neither he nor the company addressed what his future role might be.

The PQ will now look for the next leader from a list of people who passed on the chance to run just last year or were swept aside by the party members who flocked to the man known as PKP.

On Monday, Quebec’s political leaders, including Premier Philippe Couillard, eschewed politics to salute Mr. Péladeau for putting family first, but behind the scenes a long list of PQ lesser-knowns were jockeying for position.

Mr. Péladeau tried to choke back tears and often failed as he read out his resignation. He has two school-aged children with Ms. Snyder. They split just before he started in politics in 2014 and reunited a short time later. They were married last summer in a splashy media event just after he won the leadership. They split again in January after five short months and are locked in gruelling predivorce mediation.

“I’m making this decision for the good of my children,” he said. “I have to remain an example for them. I profoundly love the Parti Québécois, its activists and its [National Assembly] members.”

Mr. Péladeau’s words – that he wants to be an example for his children – echoed those of Ms. Snyder on Sunday night. She appeared on Radio-Canada’s Tout le monde en parle – a long-time ratings rival to the wildly popular variety shows Ms. Snyder produced for Mr. Péladeau’s TVA network – and issued a declaration of war after months of quiet diplomacy.

Ms. Snyder described how her lucrative 20-year business relationship with TVA suddenly dried up after she split with Mr. Péladeau. (TVA and its parent company, Quebecor, have long maintained Mr. Péladeau has no role in day-to-day operations.) She also said a coveted interview with pop music megastar Celine Dion was suddenly taken away from her and handed to another host. She expressed anxiety for her financial future after years of putting Mr. Péladeau’s corporate interests ahead of those of her own company.

Finally, she touched on mediation with Mr. Péladeau, which she described as an “enormous challenge.”

“It’s a confidential process. I can’t talk about it. But our kids go to public school, we tell them not to bully, we teach them to negotiate, to compromise. Our children learn from example. I hope we’ll be able to give a good example to our children.”

Politicians often cite the importance of family when they resign amid scandal or they’re about to be tossed by voters or their party, but there didn’t seem to be any movement to get rid of Mr. Péladeau. “For once, someone who claims he is leaving politics for family reasons is speaking the truth,” long-time friend and business associate Luc Lavoie said. “There is nothing hiding behind it.”

While no one was calling for Mr. Péladeau’s head in the PQ, it’s rare a party leader on the cusp of victory steps down and Mr. Péladeau had done nothing to improve party fortunes from its disastrous 2014 result.

On his first day of the 2014 election campaign, PKP caught then-party leader and premier Pauline Marois off guard, raising his fist and declaring his haste to make Quebec an independent country. He blew up the PQ’s go-slow approach designed to put voters at ease.

Voters fled the PQ, but he won his seat and then cruised to replace Ms. Marois in a leadership vote just 11 months 17 days ago.

He never seemed at ease in politics. He was followed by questions about conflict of interest given his status as political leader and media owner. He breached a legislative code of ethics when he urged the government to intervene on behalf of one of his companies.

He declared the PQ’s federal cousin, the Bloc Québécois, “irrelevant” and was forced to backtrack. He was caught on tape heckling a musical act at a youth gathering and badgered reporters for their efforts to reach him on his personal cellphone. He said immigrants will thwart aspirations for Quebec sovereignty and quickly apologized.

Politicians recounted tales of angry confrontations with Mr. Péladeau. He threatened to sue critics, chastised people on social media and even published the Premier’s home address. Things had calmed recently, but just last week he demoted his chief of staff.

In a Globe and Mail profile of Mr. Péladeau published almost exactly one year ago, several of his closest allies admitted they were bewildered by his choice to enter politics.

“He’s no politician,” long-time friend Bertrand Ménard said.

The Globe and Mail
Published Monday, May 02, 2016 2:03PM EDT
Last updated Tuesday, May 03, 2016 6:50AM EDT