Because her family had to stay in Virginia while her siblings finished school, she lived with Travis and Missy Parton and their four daughters, one of whom also trained at Chow's gym.

[25] Douglas competed at the 2010 Nastia Liukin Supergirl Cup, a televised Level 10 meet held in Worcester, Massachusetts, where she placed fourth all-around.

[4] Her first elite meet was the 2010 CoverGirl Classic in Chicago, Illinois, where Douglas placed third on balance beam, 6th on vault, and 9th all-around in the junior division.

Junior National Championships, Douglas won the silver medal on balance beam, placed fourth all-around and on vault, and tied for eighth on floor exercise.

[4] In October, at age 14, Douglas moved into the home of Missy Parton in West Des Moines, Iowa, to train under Liang Chow, the former coach of 2007 World Champion and 2008 Summer Olympics gold medalist Shawn Johnson.

[29][30] At the AT&T American Cup at Madison Square Garden in March, Douglas received the highest total all-around score in the women's competition, ahead of her teammate and current world champion Jordyn Wieber.

[31][32] At the 2012 U.S. National Championships in June, Douglas won the gold medal in uneven bars, silver in the all-around, and bronze in floor.

Márta Károlyi, the National Team Coordinator for USA Gymnastics, nicknamed Douglas the "Flying Squirrel" for her aerial performance on the uneven bars.

At the 2012 Summer Olympics gymnastics event at the O2 Arena (North Greenwich Arena) in London, Douglas and her teammates – Jordyn Wieber, McKayla Maroney, captain Aly Raisman and Kyla Ross (collectively nicknamed the "Fierce Five") – won the team event gold medal at the 2012 Summer Olympics.

She also became the fourth American woman to win Olympic all-around gold as well as the third straight to do so (after Mary Lou Retton in Los Angeles in 1984, Carly Patterson in Athens in 2004 and Nastia Liukin in Beijing in 2008, all of whom were at the venue and watched Douglas equal their feat.

Chow and his wife were delighted to have Douglas return to the Iowa gym, which they had not expected she would after her departure to Los Angeles in summer 2013.

At that time they were also training promising junior Norah Flatley, who many considered similar to both Douglas and Shawn Johnson in performance style.

[46] She remained in the market for a new coach until the beginning of August, when news broke that Douglas would train under Kittia Carpenter at Buckeye Gymnastics in Genoa Township, Ohio.

Douglas helped the USA win gold in the team competition and also placed 4th all-around behind defending World Champion Simone Biles, newcomer Bailie Key, and Olympic teammate Aly Raisman.

On bars, she had a high-flying piked Tkachev connected to her Pak Salto and had an excellent landing on her double layout dismount.

On Night 2, Douglas started on bars where she excelled once again on her inbar-stalder pirouettes and her piked Tkachev-Pak Salto connection but she took a large step forward on her double layout dismount and almost fell.

On beam, she had a shaky routine, with multiple balance checks and some lost connections, as well as a hop and low landing on her double pike dismount.

Douglas was named to the Senior National Team for the first time since 2012 and received an invite to the 2015 Worlds Selection Camp in September.

[53] In March 2016, following her win at the 2016 AT&T American Cup, Douglas participated at the 2016 City of Jesolo Trophy,[54] where she won the all-around title.

[56] On July 10, Douglas was named to the team for the 2016 Olympics, alongside Simone Biles, Laurie Hernandez, Madison Kocian, and Aly Raisman.

Douglas narrowly missed advancing to the all-around final to defend her title despite tallying the third-highest score in the preliminaries, since she was outscored by teammates Biles and Raisman and rules only allow two competitors from one NOC, similar to Wieber four years ago in London.

[61] In October 2022, several gymnastics media outlets, such as The Gymternet and Gymcastic, reported that Douglas had recently returned to training, this time at WOGA.

[62] In November 2022, a photograph was posted online that showed Douglas in the gym with other current WOGA athletes, further strengthening rumors of a possible comeback.

[77] On August 23, Douglas threw the ceremonial pitch at Citi Field when the Colorado Rockies played the New York Mets.

[78] On August 26, Douglas spoke about racist bullying at Excalibur Gymnastics in an interview with Oprah Winfrey and how it nearly made her quit the sport.

[84] That same month, she performed a miniature floor routine at the 2012 MTV Video Music Awards as part of the live performance by Alicia Keys and Nicki Minaj of the Girl on Fire Inferno Remix – following Douglas' success in London, Minaj had opted to end her verse with a reference to her: "I ain't tryna be that / Haters wanna see that / But I got 'em aggy / 'Cause I win the gold like Gabby.

"[85] Douglas had a small acting role on the Disney XD series Kickin It in the episode "Gabby's Gold", which aired on August 12, 2013.

[93] In 2017, after a 60 Minutes interview with Olympic gold medalist Aly Raisman who said that Larry Nassar, a former doctor for USA Gymnastics, had sexually abused her when she was 15 years old, Douglas sent a tweet saying that "dressing in a provocative/sexual way incites the wrong crowd."

[95] Douglas appeared disguised as a gray-haired, aspiring gym owner in a "Celebrity Edition" episode of Undercover Boss that first aired on May 11, 2018.

She is set to guest star as herself with Dominique Dawes and Laurie Hernandez in the episode "A Perfect 10" of the second season of the Disney+ animated series The Proud Family: Louder and Prouder, judging a gymnastics competition.