Pappas, of Greek heritage, who is the middle of three children, was born in Marietta, Georgia, and shortly thereafter moved to Kentucky with her mother and siblings. When she was twelve years old, her mother died of cancer and she relocated with her brother, Thomas, and sister, Chrissy, to Newnan, Georgia, to live with her father. She is a one-time resident of Nashville, Tennessee.
After high school she attended Georgia Military College and received a degree in General Studies. From there, Pappas attended the Gaddy's School where she earned her real estate license. She practiced real estate at Keller Williams Realty Connections in Newnan, Georgia.
In 2007, Pappas decided to audition for The Bachelor, a reality television dating game show on ABC Television. She made it to the final rose ceremony, where bachelor Brad Womack rejected both women. He was chastised by Ellen DeGeneres, who later retracted her statement. ABC Television then tapped Pappas to star in The Bachelorette. The news was broken to her by Ellen DeGeneres while she was a guest on DeGeneres' daytime talk show.
In the 2008 season of The Bachelorette, Pappas eventually rejected single dad Jason Mesnick and accepted the marriage proposal of professional snowboarder Jesse Csincsak. Their relationship lasted a few months before the engagement was called off. Mesnick went on to become The Bachelor in 2009.
In October 2008, Pappas won Fox Reality Channel's "Golden Realtini", given to the most memorable reality performer of the year.
During her engagement, in 2009, Pappas became the co-host of Get Married on Lifetime TV, reporting on wedding planning.
In late 2011, DeAnna was on the show Bachelorette Party on the Oxygen channel. Her episode was called "Big Fat Greek Bachelorette Party". The show revolves around her, her friends and family celebrating DeAnna's bachelorette party in Las Vegas, NV at the Palm's Hotel and Casino, as well as other popular Vegas attractions.
In January 2007, Pappas visited American troops in Kuwait as part of a USO visit. She was joined by actress Christine Lakin and Miss USA 2007 Rachel Smith. She also visited Afghanistan in 2009, including remote camps such as FOB Dwyer.
In August 2010, Pappas became engaged to Stephen Stagliano, whose brother, Michael Stagliano, was on season 5 of The Bachelorette. They were married October 22, 2011 in Georgia.
On August 27, 2013, it was announced that she and her husband Stephen Stagliano were expecting their first child, due in February. On September 14, 2013, the couple revealed that they were expecting a baby girl. On February 6, 2014, the couple welcomed a baby girl named, Addison Marie Stagliano.
On August 24, 2015, DeAnna announced, that their are expecting their second child, due in February 2016. The couple welcomed son, Austin Michael, on March 1, 2016.