Protester Plamen Goranov, 36, died after setting himself on fire in front of a public building in his city of Varna on Feb. 20. Goranov and other protesters accused the mayor of shady ties with an influential group that allegedly controls most businesses in Varna.
Its mayor, Kiril Yordanov, resigned on Wednesday after 13 years in office.
He denied any wrongdoing, but said he would bow to Goranov's sacrifice. "Plamen Goranov took an astounding step, and it brought about an overwhelming moral responsibility," Yordanov said at a televised news conference.
Demonstrations began in Bulgaria in mid-February against high utility bills and widespread poverty, then grew into nationwide civil unrest challenging the established order. That prompted the central government to resign.
Speaking at the last meeting of his Cabinet on Wednesday, outgoing Prime Minister Boiko Borisov said his government resigned to avoid the shedding of people's blood. "That is why today is a day of national mourning because this person—Plamen Goranov, one of the protesters—shed his own blood. That is why we made this decision," Borisov said.
He and his center-right GERB party won 2009 elections on promises to reduce crime, including widespread graft, and reform the judiciary.
This week, President Rosen Plevneliev said, "Our compatriots want decent politicians. They don't want to be robbed. They do not want to be lied to, and they want to live good lives." He will appoint a caretaker government next week to rule until early elections on May 12.
Meanwhile, several hundred people protested outside Parliament in the capital on Wednesday to demand that legislators amend the Election Code during their last few days in power to allow citizens to run for office without the endorsement of a political party.
"I think that the government betrayed us as it ran away with many of its promises left unfulfilled," said one of the protesters, Grigor Pavlov, a 30-year-old construction worker.