Haas graduated from California State University, Northridge in 1975 with a Bachelor of Science in accounting and finance. He originally majored in engineering but switched to business after the near-bankruptcy of Lockheed. Following graduation, he continued working as a machinist and CNC programmer because the pay matched the finance-sector jobs he was able to find. In 1978, he hired two employees to work with him at his small machine shop, Pro-turn Engineering.
In 1980, Haas developed a programmable indexer with a stepper motor drive to improve shop efficiency. After a positive reception at the 1983 WESTEC industry expo, he founded Haas Automation to mass-produce the HBI-5C (Haas Brothers Indexer). In 1986, Haas and a partner were awarded a US patent for the device. The company expanded into fully enclosed CNC machines in 1988, offering them at prices significantly lower than competitors.
By 1997, Haas Automation moved into a 420,000-square-foot facility in Oxnard, California, which was expanded to 1,000,000 square feet by 2005. Sales for 2014 reached a record, reportedly exceeding $1 billion worldwide.
In January 2014, Haas formally notified the FIA of his interest in entering a team in the Formula One championship for the 2015 or 2016 season. Initially using the names Haas Formula and Haas Racing Developments, he was granted an official license by the FIA on April 11, 2014. This license was granted approximately five years after Haas was released from federal prison following a conviction for felony conspiracy to commit tax evasion.
On June 4, 2014, Haas confirmed that the team’s debut would be postponed until 2016. In September 2014, the organization was renamed Haas F1 Team to better promote its involvement in the sport. To establish the team's infrastructure, Haas purchased major assets from the bankrupted Marussia F1 team in late 2014 and early 2015.
Haas founded Haas CNC Racing in 2002, purchasing a facility in Concord, North Carolina, from Hendrick Motorsports. The team debuted in the Winston Cup Series on September 30, 2002, with driver Jack Sprague. The team achieved its first victory in the Busch Series in 2004 with Jason Leffler. By 2006, the operation moved to a state-of-the-art facility in Kannapolis, North Carolina.
In late 2008, Haas partnered with driver Tony Stewart, giving Stewart a 50% stake in the renamed Stewart-Haas Racing. The partnership resulted in immediate success, with Stewart winning the 2011 Sprint Cup Championship. The team won a second Cup title in 2014 with Kevin Harvick. With a Truck Series victory by Cole Custer in 2014, Haas joined a select group of owners, including Rick Hendrick and Richard Childress, who have won as an owner in all three of NASCAR's national touring series.
Following the closure of Stewart-Haas Racing after the 2024 season, Haas opened the Haas Factory Team in 2025 as the sole owner.
In 2006, Haas began planning Wind Shear, a commercial wind tunnel designed to be the most advanced in the world. Completed in 2007, the facility features an MTS rolling road with a 70-foot-long stainless steel belt capable of speeds up to 180 miles per hour. This technology allows for the accurate simulation of track dynamics. The facility, which is 100% owned by Haas, opened to its first customer—a Formula One team—in July 2008 and currently serves NASCAR, IndyCar, and American Le Mans Series teams.
In June 2006, Haas was arrested by IRS agents on suspicion of conspiracy, witness intimidation, and filing false tax returns. While four other individuals indicted in the case pleaded guilty, Haas reached a plea agreement just before trial. He pleaded guilty to felony conspiracy to commit tax evasion and was sentenced to two years in prison and $75 million in restitution. Haas began his incarceration in January 2008 and was released on probation on May 7, 2009, after serving 16 months of his sentence.
Haas established the Gene Haas Foundation in 1999. Initially focused on Ventura County charities, the foundation expanded to support manufacturing education and training programs worldwide. This includes scholarship grants, support for CNC training programs, and the sponsorship of FIRST Robotics Competition teams. In 2022, the foundation provided more than $27 million in grants, bringing its total lifetime donations to over $175 million. Haas has also donated CNC labs to several colleges, including Cal Poly and California State University, Northridge, and provided a $1 million grant to Danville Community College in 2015.