In 2011 Hajer co-founded an organisation called Together We Build it working to promote the role of women and young people in peace building, conflict resolution and preventing violent extremism. Currently, Sharief is a co-leader coordinator leading the organisation projects on peace building. In 2016, Sharief was chosen by former UN Secretary General and Nobel Peace Prize laureate Kofi Annan to join his initiative “Extremely Together” to promote the role of young people in countering violent extremism. Late 2016, Sharief was appointed by the UN Secretary General as a member of his advisory group on youth peace and security and in particular to advise on United Security council resolution 2250 on youth peace and security. In 2017, Sharief was selected by UN Women as a member of the group of champions on women peace and security, human rights and countering violent extremism. Sharief is the recipient of the 2017 Student Peace Prize by ISFiT, and in 2020 She was named by Forbes as one of Africa's most powerful women.