When active, NOAA Ship McArthur conducted oceanographic research and assessments, primarily throughout the area of the Exclusive Economic Zone of the Pacific Coast of the United States. The 175-foot ship engaged in measurements of chemical, meteorological, and biological sampling for several large scale programs within NOAA. The majority of McArthur's work was done in several of the National Marine Sanctuaries on the west coast of the United States. The vessel was homeported at NOAA's Marine Operations Center-Pacific, in Seattle, Washington. The ship was named after William Pope McArthur and she was succeeded by the NOAA Ship McArthur II.

McArthur carried a complement of 6 officers, 17 crew members and up to 13 scientists. The scientists who carried out research aboard the ship came from many divisions of NOAA, as well as other federal and state government agencies, and academia. The ship supported a wide range of studies, from the Sustainable Seas Expedition, to marine mammal surveys in the Eastern Pacific called: CHase Encirclement Stress Studies and Oregon, California, Washington project in support of protected species research efforts.