Madison had a small role in Terminator: The Sarah Connor Chronicles during the season 1 finale, “What He Beheld”, as a girl who becomes part of a short-lived hostage situation. In the DVD extras, it is said that they thought about changing the role slightly because of its violent nature, but she insisted that they not. In 2007, Madison appeared in Nickelodeon’s television film The Last Day of Summer. She plays a girl who helps a friend during a difficult time. She also appeared in another Nickelodeon production, the television Christmas special Merry Christmas, Drake & Josh, in which she played a girl who lived with a foster family.

Madison is seen in a featured supporting role in the 2009 drama film Brothers as Isabelle Cahill, the older daughter of Captain Sam Cahill (Tobey Maguire) and Grace Cahill (Natalie Portman). For her portrayal in the film, she was nominated for both a Saturn Award and a BFCA Critics’ Choice Award. In 2010, Madison was in the drama film Letters to God, where she portrayed Samantha Perryfield, best friend of the lead character who is fighting cancer.

Also in 2010, Madison starred in her first leading role in the supernatural horror film Don’t Be Afraid of the Dark. She starred alongside Katie Holmes and Guy Pearce, portraying the role of Sally Hurst, a lonely withdrawn child who is sent to live with her father and his new girlfriend. Roger Ebert of the Chicago Sun-Times gave the film 3½ stars out of 4, calling it “a very good haunted house film” and adding that it “milks our frustration deliciously.”

In 2011, Madison had a recurring role in the Disney Channel sitcom Wizards of Waverly Place as Maxine, the girl form of Max Russo. She also appeared in Just Go with It, alongside Adam Sandler and Jennifer Aniston, as Maggie Murphy, a young girl who wants to become an actress. Madison appeared in the drama film An Invisible Sign, as the younger version of Jessica Alba’s character.

In 2012, Madison appeared in the Hallmark film A Taste of Romance alongside Teri Polo and James Patrick Stuart. She also had a guest role as the younger version of Ginnifer Goodwin’s character Snow White in the TV series Once Upon a Time. She also could be seen as the main character in the film Cowgirls n’ Angels where she played the feisty and rebellious Ida Clayton who has fantasies of finding her father, a rodeo rider. Madison appeared in another Hallmark film entitled Smart Cookie as Daisy, an eager girl hoping to prove herself as a Girl Scout. In December, she appeared in the family comedy film Parental Guidance, alongside Billy Crystal and Bette Midler.

In 2013, Madison began playing Hillary on the TV sitcom Trophy Wife, replacing Gianna LePera who played the character in the pilot. In 2014, she began playing the recurring role of Sophia Quinn in the ABC Family drama The Fosters. In 2015, she began playing Grace Russell, the daughter of Cassie Nightingale, in the Hallmark series Good Witch. Madison continued in the role until the end of the fifth season in 2019.

In 2017, it was announced that Madison would star in an adaptation of Rachel Bateman’s novel Someone Else’s Summer.

In 2018, Madison portrayed the role of Kinsey, a rebellious child in slasher horror film The Strangers: Prey at Night. She starred alongside Christina Hendricks and Martin Henderson, as her parents. The film received a mixed response from critics and was relatively successful at the box office.

Madison has served as the national youth spokesperson for Alex’s Lemonade Stand Foundation since 2010, an organization that encourages kids to fundraise and spread awareness of pediatric cancer by running their own lemonade stands. In January 2018, Madison’s first novel was published, Losing Brave, a Young-Adult Mystery which was co-written with Stefne Miller. Since November 2018, she has co-hosted the podcast Just Between Us with her sister Kaitlin Vilasuso.