James Lance Bass was born in Laurel, Mississippi. His family was devoutly Christian and conservative and his childhood was "extremely happy". As a young boy, Bass developed an interest in space, and at age 9 traveled to Cape Canaveral, Florida with his father to watch his first live space shuttle launch. Shortly after, Bass attended space camp in Titusville, Florida, and aspired to attend college and study engineering, with the hope that he would one day work for NASA. When Bass was 10 years old, his father was transferred to a different hospital, and the family moved to Clinton, Mississippi. Bass began singing in his Baptist church choir.

In 1995, during his junior year of high school, Bass was accepted into the group, which was later named 'N Sync. The group's first single, "I Want You Back" began receiving major radio play in the United States, and 'N Sync soon found themselves becoming an "overnight sensation", a period which Bass describes in his autobiography as "the death of my own innocence".

Bass dated actress Danielle Fishel of TV's Boy Meets World. Bass ended the relationship after one year, and continued to exclusively date women until he was 22.

In 2000, Bass formed a music management company named Free Lance Entertainment. The following year Bass received his first starring role in the 2001 motion picture On The Line. Bass has also lent his voice to several animated television programs.

In January 2001, Bass formed his first film production company, A Happy Place. The company changed its name to Bacon & Eggs, in 2005. In August 2002, Bass entered cosmonaut training in Star City, Russia. After several months of training, Bass received cosmonaut certification and was scheduled to fly into space on the Soyuz TMA-1 mission that was to be launched on October 30, 2002. The capsule was scheduled to fly to the International Space Station and land in a desert in Kazakhstan. Bass was eventually rejected from the program for health reasons. Bass has retained fluency in Russian, which he was required to learn during his training.

Bass revealed that he was gay in a cover story for People magazine on July 26, 2006. There had been considerable media speculation about his sexuality due to numerous paparazzi snapshots of him at gay bars and nightclubs, most notably during the preceding July 4th weekend in Provincetown, Massachusetts. Celebrity gossip blogger Perez Hilton had also reported a sighting of Bass at a gay bar with his then-boyfriend, Reichen Lehmkuhl.

Following public response surrounding his coming out, Bass announced that he was releasing an autobiography. The book, entitled Out Of Sync, was published on October 23, 2007.

In his autobiography, Bass documents two gay relationships that predated media speculation; one with a Miami, Florida native named Jesse, whom Bass lived with for two years, and another with an Idaho native named Joe. Bass began dating Amazing Race winner Reichen Lehmkuhl in early 2006. Bass described his relationship with Lehmkuhl as "very stable", however, the couple split several months later. Shortly after his split with Lehmkuhl, Bass briefly dated Brazilian model and LXTV host Pedro Andrade.

From August 2007 to March 2008, Bass dated New York-based hairdresser Ben Thigpen.

Bass formed a production company named Lance Bass Productions. It has been reported that the show will focus on the creation and development of an all-gay boy band. In 2008, Bass co-produced The Grand, and Bass's company is reported to be developing a music docudrama about the life of rock bands on tour.

On August 14, 2007, Bass began a six-month stint playing Corny Collins in the Broadway musical Hairspray, coinciding with the play's five year stage anniversary. Bass ended his run in Hairspray on January 6, 2008.