Ms. Sun, who has no family ties to the party’s revolutionary founders, started as a worker at a factory that made watches in the northeastern city of Anshan. She climbed up the ranks, working various party manager positions at two factories and later serving as the director of the municipal women’s federation.
A former colleague who lived in the same building as Ms. Sun recalled how she would knock on the door each day to offer a ride to work in her car. “What impressed me most about her was that she was easygoing and didn’t put on bureaucratic airs,” the colleague told state media in 2009.
In a rare interview, Ms. Sun spoke with pride about her blue-collar past. “I come from a worker’s background, and I have a very deep and special feeling for organized labor,” she told the Dalian Daily.
As party secretary of Dalian, a city in northeastern China, Ms. Sun honed her political acumen. She clashed with her predecessor, Bo Xilai, a brash politician from a prominent family whose meteoric rise would come to a crashing end in 2012 and pave the way for Mr. Xi to take power. She blocked Mr. Bo’s appointees and built up her own political base in the city, said Cheng Li, a scholar at the Brookings Institution.
“Bo came from a princeling family — he never hid that he was born red and entitled to many things,” Mr. Li said. “Sun came from a very humble background, and so, from Day 1, both people could not get along well.”
In 2009, Ms. Sun was named party secretary in the southern province of Fujian, where Mr. Xi had served as governor a decade earlier. When Mr. Xi was elevated to party leader in 2012, she was named to the Politburo, eventually overseeing health, education, sports and culture.
During the early days of the coronavirus outbreak in 2020, Ms. Sun led a group of experts to Wuhan on Jan. 27, four days after officials sealed the city off. The mayor of Wuhan had just offered to step down for moving too slowly.