Nationwide, many students fail to complete the key mathematics courses that are required for most STEM majors, including Precalculus. This paper describes the rationale, implementation, and impact of the redesign of Precalculus at one regional west coast institution. Prior to the redesign, pass rates in Precalculus were modest (75.8% of all students, calendar years 2009-2014). The redesigned course emphasizes active learning including group work based on conceptual questions and utilizes standards-based grading with a supporting emphasis on growth mindset. In the first three semesters of implementation, 88% of students passed the redesigned course. While the authors focus on the redesign of a Precalculus course, it is our hope that instructors of other core mathematics courses for STEM majors may find information of value in this work.