In response to the large number of high school students entering community colleges in the United States who are not prepared to begin college-level mathematics courses, and the poor success rates of students enrolled in the traditional prerequisite developmental courses that have been required for such students for many years, national attention is focused on alternative and accelerated developmental support. This dissertation documents the design, development, and implementation of the Online Corequisite College Algebra Support module, or OCCAS, a concurrently taught asynchronous online support approach for a common college-level mathematics course, as illuminated by previous research on similar approaches and guided by standard design models. This design and development dissertation focuses on two main aspects of the OCCAS: 1) The replacement of traditionally delivered prerequisite semester and multi-semester developmental courses with only the specific mathematical and developmental skills identified as appropriate and necessary for each concept or topic, and presented on an as-needed basis for the study of the college-level material, and 2) The strategic placement of tools and features intended to mitigate impediments to the effectiveness of developmental support for mathematics in general and specifically in an online context, as identified in the literature. The development portion of the study documents the process of putting this design into an active and employable format within the existing learning management system utilized at this time by the school where this study is taking place, and the utilization of existing online software to fulfill the design requirements. Formative feedback was be sought from faculty who participated in the original structuring of the connections between prerequisite and College Algebra material, and who taught earlier versions of this class in a face-to-face environment. The implementation of the module is documented and accompanied by observations, surveys, and interviews of the students in the OCCAS-supported course in order to examine perceptions and evaluations of the module and the effects of the design and development process. This dissertation concludes with a discussion of the results of the study and the resulting improvements that are to be incorporated into future iterations of the OCCAS-supported course. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]