Background and career
John D. Carmack II (born August 21, 1970) is an American computer programmer and video game developer. He co-founded the video game company id Software and was the lead programmer of its 1990s games Commander Keen, Wolfenstein 3D, Doom, Quake, and their sequels. Carmack made innovations in 3D computer graphics, such as his Carmack's Reverse algorithm for shadow volumes. In 2013, he resigned from id Software to work full-time at Oculus VR as their CTO. In 2019, he reduced his role to Consulting CTO so he could allocate more time toward artificial general intelligence (AGI). In 2022, he left Oculus to work on his AGI startup, Keen Technologies.
Carmack was born in Shawnee Mission, Kansas, the son of local television news reporter Stan Carmack. He grew up in the Kansas City metropolitan area, where he became interested in computers at an early age. He attended Shawnee Mission East High School in Prairie Village, Kansas and Raytown South High School in nearby Raytown, Missouri. Carmack was introduced to video games with the 1978 shoot 'em up game Space Invaders in the arcades during a summer vacation as a child. The 1980 maze chase arcade game Pac-Man also left a strong impression on him. He cited Nintendo designer Shigeru Miyamoto as the game developer he most admired. As reported in David Kushner's Masters of Doom, when Carmack was 14, he broke into a school with other children to steal Apple II computers. To gain entry to the building, Carmack concocted a sticky substance of thermite mixed with Vaseline that melted through the windows. However, an overweight accomplice struggled to get through the hole and instead opened the window, setting off a silent alarm and alerting police. Carmack was arrested and sent for psychiatric evaluation. He was sentenced to a year in a juvenile home. He attended the University of Missouri–Kansas City for two semesters before withdrawing to work as a freelance programmer.
Softdisk, a computer company in Shreveport, Louisiana, hired Carmack to work on Softdisk G-S (an Apple IIGS publication), introducing him to John Romero and other future key members of id Software such as Adrian Carmack (no relation). Later, Softdisk would place this team in charge of a new, but short-lived, bi-monthly game subscription product called Gamer's Edge for the IBM PC (DOS) platform. In 1990, while still at Softdisk, Carmack, Romero, and others created the first of the Commander Keen games, a series that was published by Apogee Software, under the shareware distribution model, from 1991 onwards. Afterwards, Carmack left Softdisk to co-found id Software. Carmack has pioneered or popularized the use of many techniques in computer graphics, including "adaptive tile refresh" for Commander Keen, ray casting for Hovertank 3D, Catacomb 3-D, and Wolfenstein 3D, binary space partitioning which Doom became the first game to use, surface caching which he invented for Quake, Carmack's Reverse (formally known as z-fail stencil shadows) which he devised for Doom 3, and MegaTexture technology, first used in Enemy Territory: Quake Wars. Quake 3 popularized the fast inverse square root algorithm. Carmack's engines have also been licensed for use in other influential first-person shooters such as Half-Life, Call of Duty and Medal of Honor: Allied Assault. In 2005, Carmack developed his first game for mobile phones, Doom RPG.
On August 7, 2013, Carmack joined Oculus VR as their CTO. On November 22, 2013, he resigned from id Software to work full-time at Oculus VR. Carmack's reason for leaving was that id's parent company ZeniMax Media did not want to support Oculus Rift. Carmack's role at both companies later became central to a ZeniMax lawsuit against Oculus' parent company, Meta (then known as Facebook), claiming that Oculus stole ZeniMax's virtual reality intellectual property. The trial jury absolved Carmack of liability, though Oculus and other corporate officers were held liable for trademark, copyright, and contract violations.
In February 2017, Carmack sued ZeniMax, claiming the company had refused to pay him the remaining $22.5 million (~$29 million in 2025) owed to him from their purchase of id Software. In October 2018, Carmack stated that he and ZeniMax had reached an agreement and that "Zenimax has fully satisfied their obligations to me", ending the suit. On November 13, 2019, Carmack stepped down from the Oculus CTO role to become a "Consulting CTO" in order to allocate more time to his work on artificial general intelligence (AGI). On August 19, 2022, Carmack announced that he has raised $20M for Keen Technologies, his new AGI company. On December 16, 2022, Carmack left Oculus to focus on Keen. In September 2023 John partnered with reinforcement learning researcher Richard S. Sutton, though Sutton left in 2026 to launch the AI startup Oak Lab.
Carmack claims to have maintained a sixty-hour work week, working a 10-hour day, six days a week, throughout his career. He has spoken publicly about the importance of long hours of uninterrupted focus in his work. Not only does high intensity allow him to make progress more quickly, but long hours are also critical to maintaining a focused mindset over time. Despite working such a demanding schedule, he has never experienced burnout. Carmack is also known for taking week-long programming retreats. These retreats involve a solitary, uninterrupted period away from his normal routine often sequestered in a random city and hotel. The goal of these retreats is to allow Carmack to operate at full cognitive capacity, tackling a specific, difficult problem or learning a new skill. The solitude and physical isolation of these retreats offer an environment for deep focus and reflection, making them an essential part of Carmack's creative process. Carmack was vocal about his frustration with the bureaucratic inefficiencies he encountered during his time at Meta. In his departure memo, he stated, "We have a ridiculous amount of people and resources, but we constantly self-sabotage and squander effort," he wrote. "I have never been able to kill stupid things before they cause damage, or set a direction and have a team actually stick to it." Carmack subscribes to the philosophy that small, incremental steps are the fastest route to meaningful and disruptive innovation. He compares this approach to the "magic of gradient descent" where small steps using local information result in the best outcomes. According to Carmack, this principle is proven by his own experience, and he has observed this in many of the smartest people in the world. He states, "Little tiny steps using local information winds up leading to all the best answers."
