This paper will review landmarks in American and European marine noise science and management, reflecting a changing scientific and regulatory focus from acute, near-field effects on beaked whales to impacts on a wider range of species and their “acoustic habitat” over broader temporal and spatial scales. Increases in the scale of noise associated with human activities has led to greater levels of research and management. Although mitigation within the United States and Europe is principally aimed at reducing risk from acute effects of individual activities, regulators are moving in significant ways towards cumulative, multi-sectoral impact management. Solutions to be discussed include source-quieting methods and technologies for commercial shipping, pile driving, and seismic survey noise; spatial management through the use of programmatic and strategic environmental assessments, particularly for active sonar; and noise budget caps—for example, as a potential outcome of the European Union (EU) Marine Strategy Framework Directive. This paper also will identify the most pressing data needs for conservation management, including data on impacts (e.g., the impacts of offshore windfarm construction and operation on baleen whales), effective mitigation methods and technology (such as noise reduction standards for individual commercial ships), and cumulative effects (including impacts of chronic stress on cetacean morbidity, survival, and reproduction).