Born in Lima on 16 August 1949. She was the first daughter and the second of the seven children of Fernando Villarán Duany and Josefina de la Puente y Lavalle. Villarán studied at L’École Nouvelle of Miraflores and Colegio Sagrados Corazones Chalet of Chorrillos.

In 1995 Villarán was elected national co-ordinator of the Party for Social Democracy (Partido por la Democracia Social – Compromiso Perú, PDS). She became Minister for Women and Social Development during Valentín Paniagua’s transitory government in 2001, and in 2002 she assumed the role of Police Ombudsman (Defensora de la Policía).

From 2002 to 2005, she served as a member of the Organization of American States’s Inter-American Commission on Human Rights (IACHR), serving as rapporteur on child rights and later on women’s rights, as Second Vice President of the Commission in 2004, and First Vice President in 2005. She took part in IACHR human rights and conflict missions in Colombia and Guatemala.

In 2008, she was elected to the United Nations Committee on the Rights of the Child.

In 2009 she announced her candidacy for Mayor of Lima as leader of the Social Force Decentralisation Party (FS), which had been formed by the merger of the PDS and eight other centre-left parties in October 2007. Her candidature was backed by three smaller centre-left groups.

After a slow start to her campaign, in the final weeks Villarán overtook the longtime favourite candidate Lourdes Flores to win with 1,743,712 votes, representing 38.393% of the valid votes. She assumed office in January 2011.

There was a referendum held to recall her from office, which was held on March 17, 2013. She survived the recall but 20 members – including spokesperson against her recall Marisa Glave – of the city council were recalled. However, she lost her 2014 re-election bid to former mayor Luis Castañeda Lossio, who took office on January 1, 2015.