He founded the nonprofit organization Inner-City Muslim Action Network in 1997, working as its executive director for many years, and has been involved in a number of efforts to improve the welfare of residents of the South Side of Chicago.

[7][6] The Inter-City Muslim Action Network also hosts cultural events, such as the Takin' It To The Streets festival in Marquette Park,[8] and has opened a second chapter in Atlanta.

[9] In 2020, Nashashibi was the executive producer, lyricist, and guitarist on an album, This Love Thing, with fellow activist Drea D'Nur[10] and sound engineer Elijah Hooks.

[11] In 2009, Nashashibi was named one of the 500 most influential Muslims by The Royal Islamic Strategic Studies Centre and the Prince Alwaleed Bin Talal Center for Muslim-Christian Understanding by Georgetown University.

[13] In 2017, Nashashibi was named a MacArthur Fellow, for "confronting the challenges of poverty and disinvestment in urban communities through a Muslim-led civic engagement effort that bridges race, class, and religion".