Jo Cox fought against poverty and discrimination in developing countries, worked in Parliament for a solution to the civil war in Syria and campaigned for Britain to remain in the European Union.
In charity work and politics, she took up causes across the globe, from some of the world's most dangerous countries to her home constituency in Yorkshire.
"I've been in some horrific situations where women have been raped repeatedly in Darfur. I've been with child soldiers who have been given Kalashnikovs and kill members of their own family in Uganda," the Labour Party lawmaker told the Yorkshire Post last December. "That's the thing that all of that experience gave me — if you ignore a problem it gets worse."
Cox was killed Thursday by a gun- and knife wielding attacker in her small-town constituency, one week before what would have been her 42nd birthday.
A day earlier she had campaigned on the River Thames in London with her husband and two young children. Her husband, Brendan Cox, posted images on Twitter of the family in an inflatable dinghy, waving a flag supporting continued British EU membership ahead of the June 23 referendum.
"Jo believed in a better world and she fought for it every day of her life with an energy and a zest for life that would exhaust most people," Brendan Cox, said in a statement Thursday after her death was announced by police.
Besides her career in politics, Jo Cox described herself on her personal website as an avid runner, cyclist and mountain climber.
She was elected to the House of Commons last year as a Labour Party lawmaker representing the constituency of Batley and Spen in West Yorkshire. She divided her time between the family's houseboat on the Thames and a home in Batley and Spen.
In Parliament she made finding a solution to the Syrian civil war a top priority. She was critical of Britain's reluctance to deepen its military involvement against Islamic State militants, but abstained in a vote on airstrikes because she said the plan didn't devote enough attention to stopping the "brutality" of President Bashar Assad.
"I'm not against airstrikes in principle," she said. "In fact, as part of an integrated strategy for Syria they are almost certainly a necessary part. But airstrikes are a tactic not a strategy, and outside a strategy I fear they will fail."
Cox grew up in West Yorkshire in a working class home. Her mother was a school secretary and her father worked in a toothpaste factory in Leeds.
When she finished her studies at Cambridge in 1995, she was first in her family to graduate from a university. But she described her years at Cambridge as difficult, telling the Yorkshire Post that is where she realized that "where you were born matters."
"I didn't really speak right or know the right people," she said. "I spent the summers packing toothpaste at a factory working where my dad worked and everyone else had gone on a gap year. To be honest my experience at Cambridge really knocked me for about five years."
After university she spent a decade working in various roles for Oxfam, the British aid agency. She then joined Sarah Brown, the wife of former Prime Minister Gordon Brown, on a campaign to reduce the number of women dying in pregnancy and childbirth. She also worked with several other charities, including Save the Children, the Bill and Melinda Gates Foundation and the anti-slavery group The Freedom Fund.
For four years she chaired the Labour Women's Network, a group campaigning for more women to run for political office.
Cox initially backed Jeremy Corbyn for the Labour leadership after Ed Miliband resigned. She later said she regretted that decision and instead voted for one of his opponents, Liz Kendall.
Corbyn on Thursday praised Cox's record of public service and humanitarian work.
"Jo Cox died doing her public duty at the heart of our democracy, listening to and representing the people she was elected to serve," he said. "It is a profoundly important cause for us all."