John D. Carmack II was born in Shawnee Mission, Kansas. From a young age, he demonstrated a keen interest in electronics and computers, foreshadowing his future passion and innovative career path. His early fascination with technology laid the groundwork for his later groundbreaking achievements.

Carmack's early forays into programming began during his teenage years. Using an Apple II computer, he started experimenting with various programming languages and concepts, solidifying his deep understanding of computer architecture and graphics. This period was critical in fostering his natural talent and enthusiasm for software development.