[1] In 2008, Dumas, aged 33, was elected chief of the Mathias Colomb First Nation.
[1][2] Dumas has participated in the Idle No More movement,[1] and in activism against the Hudbay Minerals company beginning in 2013.
[8][9] In March 2022, Dumas was suspended from the position following allegations of sexual harassment from a former female staff member;[10] he was formally removed in August 2022 following an independent investigation into the matter.
[9][11] In August 2023, Dumas was sued by the former staff member, who alleged he had raped and sexually harassed her.
[13] After being removed from the grand chief position, Dumas took the role of Health Services director at Quest Health Clinic Inc.[14] Dumas' son, who had cystic fibrosis, died in 2019.