"[3][4] During the Nobel Peace Prize award ceremony at Oslo City Hall held on 10 December 2017, Fihn jointly received medals and diplomas on behalf of ICAN alongside Setsuko Thurlow, who survived Hiroshima in 1945.

In 2009, she participated in an internship at the Women's International League for Peace and Freedom (WILPF), and was involved in the work of the Conference on Disarmament and the United Nations Human Rights Council.

In 2018, Fihn produced the film The Day the World Changed,[7] the first-ever virtual reality memorial experience dedicated to those directly affected by nuclear warfare dating back to 1945.

While in Japan, Fihn signed a petition placed in the museum calling for the early conclusion of the Treaty on the Prohibition of Nuclear Weapons (adopted in July 2017).

[10][11] Under Fihn's leadership, ICAN has been the main civil society actor working alongside governments to achieve a strong and effective nuclear weapons ban treaty.

[15][16] The Tribeca Film Festival honored Fihn with the Special Lifetime Achievement Award at the ninth annual Disruptive Innovation ceremony in April 2018.