Justice MacEachern practised with the Ottawa law firm of Nelligan O'Brien Payne LLP from 1994 until her appointment to the Ontario Superior Court of Justice. She served as head of the firm's family law group from 2007 until her appointment and as head of the firm's wills and estates group from 2015 to 2018. Her practice included family law; wills and estates; civil litigation and personal injury law; and human rights, constitutional, and equality law. At the same time, she remained involved in personal injury litigation, primarily in cases involving sexual violence. She has also remained engaged in human rights, constitutional, and equality work, including in the areas of violence,propagation of hate, defamation, and prisoners' rights.Justice MacEachern was involved as legal counsel in a number of precedent-setting cases, including in the area of same-sex spousal recognition and the right to marry (Egan, M. v. H., Trinity Western, Little Sisters, the Marriage Reference, and other cases); unjust enrichment claims for common-law spouses (Vanasse v. Seguin/Kerr v. Baranow); and prisoners' rights cases (R. v. Ewert).She served as co-chair of the County of Carleton Law Association (CCLA) Family Law Institute Annual Conference beginning in 2013, and was a member of the conference planning committee beginning in 1999. In addition, she was a founding member of the CCLA's Diversity Committee.Justice MacEachern has acted as pro bono legal counsel to both the Canadian Association of Elizabeth Fry Societies and (EGALE). She was the 2018 recipient of the Ontario Bar Association's Award of Excellence in the Promotion of Women's Equality.
