As K-12 computer science education mandates rapidly evolve across America, government officials, technology industry executives, and school leaders recognize such efforts' intellectual and economic importance. Specifically in Tennessee, a unanimous vote from the Tennessee General Assembly resulted in the passage of Chapter 979 of the Public Acts of 2022, which required all Local Education Agencies (LEAs) and public charter schools to provide K-12 students with grade-level appropriate computer science education. For Grades K-5, this included computer science integration into all core academic standards. This quantitative experimental study aimed to determine which factors influenced elementary in-service teachers' self-efficacy to learn, teach, and integrate computer science during professional development. Data were collected at a Tennessee Department of Education "Reach Them All" computer science professional development workshop held in a West Tennessee school district and facilitated by CS Ambassadors trained by the Tennessee STEM Innovation Network. The sample included 26 participants who were current K-5 teachers. The researcher developed the Teacher Self-Efficacy in Computer Science Survey (TSCSS) instrument, based on the Computer Science Teacher Association (CSTA) computer science teacher standards, to measure teacher self-efficacy to learn CS knowledge and skills, teach using CS classroom practices, and integrate using CS instructional design. Participants completed the TSCSS as a pre- and posttest, and the experimental group was given the treatment of selecting their precurated learning activities during four of the 12 sessions of the "Reach Them All" workshop. The data revealed that the treatment (autonomy to choose learning activities) had no statistically significant impact on learning, teaching, or integrating computer science. In fact, the adjusted mean values suggested that teacher autonomy may have hindered teacher belief they can learn, teach, and integrate computer science. In addition, teacher characteristics and teacher CS exposure were also found to have no statistically significant difference on teacher self-efficacy to learn, teach, or integrate computer science. However, the adjusted mean values implied patterns that LEAs should consider when selecting teachers for CS leadership roles, such as teachers who are younger than 26 years old, experienced teaching multiple grade levels during one academic year, or have 3-5 years of teaching experience. [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/en-US/products/dissertations/individuals.shtml.]