Now she's coming back home after her stint at the United Nations, and if Chile's left has its way, she will add another item to that list: savior.
Bachelet, 62, who announced her return Friday night, is widely seen as the center-left opposition's only hope of winning the Nov. 17 presidential election and taking power back from the conservative establishment ushered in when Sebastian Pinera won the presidency in 2010 after she left office.
The popularity of this Andean country's only woman president is high. She ended her presidential term with nearly 80 percent approval ratings.And a recent poll by CEP Estudios Publicos consultancy said if the elections were to be held today she would easily win the presidency with 54 percent of the votes.
In announcing the end of her work at the U.N., Bachelet said only that she was going back to Chile and gave no specifics on timing.
She also did not mention the presidential race despite intense pressure in Chile for her to make her plans known although there is a widespread expectation that she will run.
Her silence has frustrated not only her opponents but especially her sympathizers.
"We don't have a plan B. I'm serious. In the opposition we're just not prepared for a negative response from Bachelet," said Jaime Quintana, president of the Liberal Party for Democracy, one of the parties in the center-left coalition.
Whoever runs will have to be ready to tackle mounting social demands and frequent protests that already troubled Bachelet during her presidency and have harried Pinera even more. Pinera is the most unpopular president since Chile returned to democracy in 1990 after the dictatorship of Gen. Augusto Pinochet.
Chile is respected for its fast-growing economy and transparent institutions. The country has continued to grow under Pinera and enjoys a record-low jobless rate. But it also has the worst inequality rate among the 34 countries of the Organization for Economic Co-operation and Development.
Millions of Chileans have participated in protests demanding a wider distribution of Chile's copper riches, free education and the return of ancestral lands to Mapuche Indians in a southern region where members of Chile's largest indigenous group often clash with timber companies and landowners.
Most Chileans also oppose plans to tame two of the world's wildest rivers and build more than 1,000 miles (1,600 kilometers) of power lines between them and the grid that powers the capital. Some mass marches against the $7 billion HydroAysen project have turned violent in energy-strapped Chile.
"During Bachelet's government and Pinera's administration there was a huge shift in Chile when it comes to development," said Marta Lagos, head of the Santiago-based polling firm Mori.
She noted per-capita income has surged since Bachelet was elected in 2006 and said Chileans widely feel the country has risen into the ranks of the developed world although many people are still poor.
"The protests partly come from people asking: 'If Chile is so rich, why am I not successful?' Whoever takes over will have to deal with more people saying: 'Give me a slice of that cake,*" Lagos said.
Bachelet's road to prominence has been a long one, and hard at the start.
Her father, air force Gen. Alberto Bachelet, died in 1974 following torture in prison after Pinochet's military convicted him of being a traitor for opposing the coup that ousted Marxist President Salvador Allende. Two Chilean military officers were charged last year with the death.
Bachelet herself was arrested along with her mother in 1975. It's an ordeal that she prefers not to talk about, saying only in her autobiography that she suffered "physical hardships." Using the family's political connections, she went into exile in Australia and the former East Germany.
When she returned to Chile in 1979, she studied medicine, specializing in pediatrics. She began working at an organization that helped children with mental health problems whose parents had been victims of the dictatorship.
At the same time, Bachelet rose through the ranks of the Socialist party and became a key player in the center-left coalition that dominated Chile's government for almost 20 years after Pinochet gave up power.
Her recent silence about her plans is in stark contrast with her normal manner. She easily breaks into casual chats and often improvises during speeches most often tossing in jokes or unplanned commentaries, said Francisco Javier Diaz, her former speech writer.
Her charisma and ability to evoke a close relationship with people has on occasion helped her overcome mistakes.
"When people feel so close, when they feel this is a caring person, they try to justify even the unjustifiable or forgive her faults," said Giorgo Agostini, a sociologist.
Those faults have not been few or small. In 2010, just 11 days before the end of her presidential term, the government's national emergency office failed to issue a tsunami warning to evacuate the coast after a magnitude-8.8 earthquake. More than 500 people were killed in the quake and the tsunami it set off.
Student protests that still bedevil Chile began during Bachelet's term and grew into strikes and school takeovers that forced her to shuffle her Cabinet. She sought unsuccessfully to calm the movement by naming a committee to discuss student demands.
Students are unhappy with Chile's poor quality public schools and unprepared teachers. The best college education requires going to expensive, private universities, and banks make education loans at high interest rates most Chileans can't afford.
Bachelet, who worked to bolster social programs while also encouraging business, won praise for shepherding Chile through the world economic crisis. Although growth stumbled and the jobless rate rose, she used government reserves to help the poorest Chileans during the hardest times.
Twice divorced, Bachelet is known as a caring mother and as an astute negotiator.
She put behind her past and helped the discredited military regain its status after Pinochet's traumatic dictatorship. One of her most emblematic moments came when she was named Latin America*s first woman defense minister during the government of President Ricardo Lagos.
Now Chileans wait to see if she's ready to jump back on the political stage.
Associated Press writers Edith M. Lederer at the United Nations in New York and Luis Andres Henao contributed to this report.
Eva Vergara on Twitter: https://twitter.com/evergaraap