Cases of nontuberculous Mycobacterium (NTM) are on the rise across North America. This is the first clinical description of a 31-year old male patient in North America with Mycobacterium kansasii who met DSM-5 diagnostic criteria for anorexia nervosa (AN) and obsessive compulsive disorder (OCD), and who was engaged in specialized outpatient treatment of an eating disorder. The patient did not disclose at intake assessment that he was experiencing symptoms of a persistent cough, blood in his sputum, or that he was simultaneously being assessed outside of the eating disorders program for NTM until he had a positive smear for Mycobacterium kansasii in March 2017. The patient made progress in treatment in his weight status and some psychological symptoms despite the concurrent NTM symptoms. However, later treatment attendance was negatively impacted by the side effects of his medication regime for NTM and careful follow-up was required to monitor for potential interactions between his treatment for NTM and psychiatric medication. This case report provides an initial window into clinicians' ability to treat a patient with a concurrent eating disorder and an NTM infection and lessons learned in the process. LEVEL OF EVIDENCE: Level V: Opinions of respected authorities, based on descriptive studies, clinical experience, or reports of expert committees.