Littrell even lived with Samantha's family for two years.In 1998, after their separation, she released the book What You Wanna Know: Backstreet Boys Secrets Only a Girlfriend Can Tell, about their relationship and the Backstreet Boys.For a long time, Littrell had wanted to record Christian music—what he calls "pop positive" music. 3 on the Christian charts, and has sold over 100,000 copies. During this time, he maintained his duties as a member of the Backstreet Boys.
Littrell and Wallace were married on September 2, 2000 at Peachtree Christian Church in Atlanta, Georgia. Together they have one son, Baylee Thomas Wylee Littrell, born on November 26, 2002.
A devout Christian, Littrell has stated that he believes it is the duty of Christians to be open about their faith, saying, "I think as Christians we need to join hands and mount up together and lift God up and talk about our faith publicly and talk about all of the things God has done for us in our life to touch other people." Littrell, who has been a born again Christian since the age of eight, has said that he attributes his success in life to God, and that his faith has always been "the utmost important thing" in his life.
During this time they released four albums, Backstreet Boys, Backstreet's Back, Millennium and Black & Blue followed by a greatest hits album, The Hits: Chapter One.
After a three-year gap, they released their comeback album, Never Gone followed by Unbreakable, This is Us and In a World Like This.
An open heart surgery in 1998 closed the hole he had in his heart, as he said on his Hour of Power interview in 2007.
After that he founded the Brian Littrell's "Healthy Heart Club" for kids, a non-profit organization that assists children with heart conditions through medical, financial and practical help.
The band manager Lou Pearlman marketed the Backstreet Boys in Europe, where they became commercially successful in 1995.
They became hugely popular in Europe, Latin America and the United States in the late 1990s and the early 2000s.
In 1997, Littrell was instrumental in bringing a lawsuit against the group's managers Lou Pearlman and Trans Continental claiming that Pearlman has not been truthful about the earnings made by the group. 1 on Reach FM's Top 40 chart and the R&R Christian Inspirational Chart, staying there for three weeks.
In the following year, Mc Lean, Richardson and Dorough joined the lawsuit which eventually resulted in a number of settlements, details of which were not disclosed. The second single was "Wish" and, in 2007, the third single, "Over My Head", was released.
In October 2009, Littrell became infected with the H1N1 virus, causing the cancellation of the Backstreet Boys This Is Us promotional tour.