Jolie first witnessed the effects of a humanitarian crisis while filming Lara Croft: Tomb Raider (2001) in war-torn Cambodia, an experience she later credited with having brought her a greater understanding of the world.[95] Upon her return home, Jolie contacted the United Nations High Commissioner for Refugees (UNHCR) for information on international trouble spots.[94] To learn more about the conditions in these areas, she began visiting refugee camps around the world. In February 2001, she went on her first field visit, an 18-day mission to Sierra Leone and Tanzania; she later expressed her shock at what she had witnessed.[94] 
In the following months, Jolie returned to Cambodia for two weeks and met with Afghan refugees in Pakistan, where she donated $1 million in response to an international UNHCR emergency appeal,[96][97] the largest donation UNHCR had ever received from a private individual.[98] She covered all costs related to her missions and shared the same rudimentary working and living conditions as UNHCR field staff on all of her visits.[94] Jolie was named a UNHCR Goodwill Ambassador at UNHCR headquarters in Geneva on August 27, 2001.[99]
Secretary of State Condoleezza Rice and Jolie at a UNHCR celebration of World Refugee Day in June 2005
Over the next decade, she went on more than 40 field missions, meeting with refugees and internally displaced persons in over 30 countries.[100] In 2002, when asked what she hoped to accomplish, she stated, "Awareness of the plight of these people. I think they should be commended for what they have survived, not looked down upon."[96] To that end, her 2001–02 field visits were chronicled in her book Notes from My Travels, which was published in October 2003 in conjunction with the release of her humanitarian drama Beyond Borders.
Jolie aimed to visit what she termed "forgotten emergencies," crises that media attention had shifted away from.[101] She became noted for travelling to war zones,[102] such as Sudan's Darfur region during the Darfur conflict,[103] the Syrian-Iraqi border during the Second Gulf War,[104] where she met privately with U.S. troops and other multi-national forces,[105] and the Afghan capital Kabul during the war in Afghanistan, where three aid workers were murdered in the midst of her first visit.[102] To aid her travels, she began taking flying lessons in 2004 with the aim of ferrying aid workers and food supplies around the world;[16][106] she now holds a private pilot license with instrument rating and owns a Cirrus SR22 and Cessna 208 Caravan single-engine aircraft.[107][108][109]
On April 17, 2012, after more than a decade of service as a UNHCR Goodwill Ambassador, Jolie was promoted to the rank of Special Envoy to High Commissioner António Guterres, the first to take on such a position within the organization. In her expanded role, she was given authority to represent Guterres and UNHCR at the diplomatic level, with a focus on major refugee crises.[110] In the months following her promotion, she made her first visit as Special Envoy—her third over all—to Ecuador, where she met with Colombian refugees,[111] and she accompanied Guterres on a week-long tour of Jordan, Lebanon, Turkey, and Iraq, to assess the situation of refugees from neighboring Syria.[112] Since then, Jolie has gone on over a dozen field missions around the world to meet with refugees and undertake advocacy on their behalf.[100][113]