[5] He previously held the Duns Scotus Chair of Spirituality at Catholic Theological Union in Chicago, and taught at several other academic institutions.

He previously served several terms on the International Thomas Merton Society Board of Directors[11] and is a former columnist at America.

[18][19] Additionally, Horan has advocated for a number of other justice issues in academic and popular venues, including in response to the global climate crisis, ecospirituality, and antiracism.

[20] On October 3, 2024, Horan announced that he would be leaving the Franciscan order and ministry as a priest, and would be petitioning the Holy See for a dispensation from the rights and obligations of the clerical state ("laicization").

[2] Citing the COVID-19 pandemic as a catalyst, Horan said that "subtle changes and growth" and a "wrestling with" where his passions were helped determine his decision.