Background: Despite ongoing calls for prioritizing K-12 computer science (CS) education, an enduring gender gap exists. Objective: We explored one high school CS program where female participation was consistently higher than state averages to better understand how the program was developed. Method: Using a case study method, data were collected over three-months through interviews, observations, course documents, student reflections, and researcher reflections. Constant comparative analysis was employed to analyze data throughout and following data generation. Findings: Recruitment and teacher support were key practices. Recruitment practices included letter writing campaigns and recruiting from introductory CS courses. Teacher support came from counselors, administrators, and other teachers. While the CS program was consistently more gender-inclusive, the focus when building the program had been on supporting "all" students, not only female students. Implications: Recruitment should be active and purposeful, but using academic indicators for targeted recruitment campaigns can limit student exposure. Teachers need support for broadening participation, particularly from counselors and administrators, who must also be aware of what CS is and their role in these efforts. Opportunities for coteaching within CS programs can be beneficial for growth. Overall, broadening participation must be a holistic effort, supported by school-wide stakeholders, not only CS teachers.