Ordained in the Presbyterian Church USA (PCUSA), Rev. Dr. Simpson serves as Pastor of Nauraushaun Presbyterian Church in Pearl River, NY, and holds the role of Treasurer and Trustee for the Presbytery of Hudson River in upstate New York. At the denominational level, he chairs the Environmental Justice and Climate Change sub-committee of the Mission Responsibility through Investment, a shareholder advocacy group of the PCUSA.

Along with his pastoral responsibilities, Rev. Simpson is also the co-founder of the Hudson Valley Environmental Justice Coalition, an informal coalition of forty plus Hudson Valley based not-for-profit and faith-based organizations focused on uplifting the voices of people of color working in environmental and climate justice.

His work with not for profits ranges from his serving as co-chair of the Center for Earth Ethics'Advisory board, former chair of the board of Transart Inc and between 2020-21 served as the co-chair of the Hudson Valley/Catskills Climate Reality Project Chapter. In 2020, he was nominated and voted by the membership to the Hudson River Sloop Clearwater board and in 2021 Rev. Simpson was nominated to the Ulster County legislature by current Congressman Patrick Ryan to serve on the SUNY Ulster Community College Board of Trustees, beginning his term there in January 2022. In the same month he was voted to the board of Riverkeeper Inc. and in November 2022 was elected as Councilperson to the Town Board of Hurley, NY.

Of particular interest to Rev. Simpson is in equipping students with skills to become exceptional leaders in STEM fields, with a sensitivity toward STEM education, environmental and climate justice issues.

Rev. Simpson holds a doctorate in organic chemistry from the University of the West Indies, post-doctoral training in molecular biology and genomic physiology from the University of Massachusetts Medical School, and two Master's degrees from Union Theological Seminary in the City of New York. He lives in Ulster County with his wife, Suzanne, daughter Amara, and their two cats, Calvin (no relation to John Calvin) and Luther (no relation to Martin Luther).