Representative Lujan was born in San Antonio where his mother was a local public-school principal, and his father was a Southside minister. He learned from his parents at a young age the importance of serving others.

After graduating, Lujan served the San Antonio community for five years as a Deputy in the Bexar County Sheriff's department before accepting a job with the San Antonio Fire Department, a position he held for over 25 years. While serving as a firefighter, he worked closely with elected officials at all levels of government to advocate for additional tools and training for first responders to help them better serve their communities. Today, Representative Lujan is a business owner who helped grow a small local IT firm into a thriving business that employees over 500 people in the HD 118 community.

John and his wife, Freda, have been married for 37 years and live on a small ranch in South San Antonio. They are proud parents of five boys, three of whom are adopted. Representative Lujan volunteers as a board member with Southside Cardinals Youth Sports League and is a Sunday School teacher at Southside Baptist Church, where his family attends church.