Dr. Holifield previously interned at the United States Environmental Protection Agency, where she helped create site safety plans and worked on the chemical reference database to aid in superfund and hazardous waste management (1986). From 2006 to 2011, as an Adjunct Professor, she taught the geography of soils and soil properties to upper-level undergraduates at the University of Maryland Baltimore County. During this time, she held a dual appointment at Stevenson University as a Professor of Biology in Human Biology, Contemporary Health, Microbiology, and Physical and Earth Sciences (2007-2011). Dr. Holifield also taught Biology, Environmental Science, and Environmental Law and Regulation as an Adjunct Professor at the Community College of Baltimore County (2010-2014).

Dr. Holifield joined the USDA in 1991 as a soil scientist for the US Forest Service, a role she served until 2022 when she held numerous other positions within the USDA and the Forest Service. As a soil scientist, she conducted research, taught environmental science, and coordinated outreach, earning her numerous awards from the USDA, including the 2020 Forest Service Northern Research Station Superior Service Award, the 2016 Chief's Award for Distinguished Service, and the 2010 Forest Service Northern Research Station Outstanding Location Civil Rights Award, among others. Additionally, in 2020, Dr. Holifield worked as the National Program Manager of the Urban and Community Forestry program, where she worked across regions to help stakeholders make sound decisions related to urban and community lands. Afterward, she became Program Manager for the Forest Service and NASF Urban Committee 2021 State Urban Forest Resilience Grant Program.

Dr. Holifield currently works as the National Program Manager for Cooperative Forestry at the USFS in Washington, D.C., where she serves within the Urban and Community Forestry Program. She oversees policy, partnership development, educational and community engagement, and strategies for equitable urban forestry programs nationwide. Her work involves collaborating with stakeholders at various levels, including community organizations and state and federal actors. As a result of the Inflation Reduction Act, her role and the program have become critical to achieving climate and equity goals. Dr. Holifield is also a member of the American Pathology Society, Alpha Zeta Agricultural Fraternity, the Ecological Society of America, and the Soil Science Society of America. Among highlights in her career include her current role with the USFS, receiving a dual PhD from SUNY ESF and Syracuse University in Forest and Resource Management, being the first African American woman to complete the specialized degree program at the university, and engaging in further educational opportunities at MIT, Yale University, and Syracuse University.