The definition of environmental engineering has been updated to be: develop solutions for problems of ''planetary health,'' a phrase that concisely and inclusively captures the breadth of public health, global health, and one health. This new definition is consistent with the missions of the American Academy of Environmental Engineers and Scientists and Association of Environmental and Science Professors (AEESP), and it encompasses the environmental engineering grand challenges of the National Academies of Science, Engineering, and Medicine. The updated job description of environmental engineers is both an opportunity and a challenge. To solve problems of planetary health, environmental engineers will apply foundational principles of engineering science and engineering design, including sustainability and life-cycle assessment, all of which is well established in the ABET program criteria for educational programs in environmental engineering. It is also essential to improve social contracts to promote justice, equity, diversity, and inclusion across individuals, communities, and countries. The skills and practices to solve this second challenge, for example, environmental justice, are still emerging in the field. There are strong parallels between the field of environmental engineering and the profession of nursing, for which the 150-year-old mandate of Florence Nightingale is still relevant: promote wellness, prevent illness, and cure disease, which are best supported by a healthy environment, including fresh air, pure water, sanitation, hygiene, and sunlight. Environmental engineering, nursing, and other professions of caregiving can partner and share strategies to achieve planetary health.