Mattson is a former president of the Islamic Society of North America (ISNA)[1][2] and was described as "Perhaps the most noticed figure among American Muslim women" in a 2010 New York Times article.

[8] While serving as the vice-president and president of the Islamic Society of North America, Mattson worked on a number of occasions with United States government officials.

She invited Rabbi Eric Yoffie, President of the Union for Reform Judaism,[12] to speak at the organization's annual convention in Chicago in 2006.

Mattson spoke the next year at the group's Biennial where she received a standing ovation and announced "a new partnership that promotes interfaith dialogue and other relationship-building activities" between the two organizations.

[17][18][19] Mattson is an original signatory of "A Common Word"[20] and has participated in many Christian-Muslim conferences and dialogues with the Jordanian Royal Aal al-Bayt Institute for Islamic Thought.

[24] Her book, The Story of The Qur'an: its history and place in Muslim Life (now in its 2nd edition) was chosen in 2012 by the National Endowment for the Humanities for inclusion in its "Bridging Cultures" program.

[28] Mattson is also the Founder and Director of The Hurma Project - an initiative to help Muslim communities prevent and act against spiritual and sexual abuse by those in position of religious authority and influence.

[29] She explained in an interview with Haute Hijab magazine that she was motivated to act after witnessing on multiple occasions how the community was not able to appropriately acknowledge and deal with such situations.

She said, "I realized we needed something broad and interdisciplinary to examine the scope of the problem, have a good understanding of all of the dynamics and develop educational materials and processes that we can bring to the community.

In a 2007 essay, Mattson condemned "Exclusivist, triumphalist, communal identities (religious or political)" that justify violent attacks on other groups.