McCurdy started her acting career in 2000 at the age of eight on MADtv. Since then she appeared in television series, including CSI: Crime Scene Investigation, Malcolm in the Middle, Lincoln Heights, Will & Grace, Penguins of Madagascar, Zoey 101, True Jackson, VP, Law and Order SVU, Medium, Judging Amy, The Inside, Karen Sisco, Over There and Close to Home. In 2003, she had the chance to act with her inspiration, Harrison Ford in the movie Hollywood Homicide. In 2005, she was nominated for a Young Artist Award for Best Performance in a Television Series – Guest Starring Young Actress for her performance in Strong Medicine as Hailey Campos. She has also appeared in several commercials, such as one for Sprint and a public service announcement on crossing the road safely.
From 2007 to 2012, she had a starring role in the Nickelodeon TV series iCarly opposite Miranda Cosgrove, Nathan Kress, Jerry Trainor, and Noah Munck, as one of Carly Shay's best friends Sam Puckett. In 2008, she was nominated for a Young Artist Award for her work on iCarly, and for her performance as Dory Sorenson in the TV movie The Last Day of Summer. She was nominated for a 2009 Teen Choice Award, in the Favorite TV Sidekick category for her work on iCarly. She played Bertha in Fred: The Movie, a movie based on a YouTube series about Fred Figglehorn. On December 1, 2011, she signed into United Talent Agency's cast of actors and performers for film, TV, music and other areas, to a deal starring her in a pilot vehicle. She was previously with Creative Artists Agency and Larry Galper. McCurdy currently stars alongside Ariana Grande in the Nickelodeon series Sam and Cat, reprising her role as Sam Puckett, with Grande reprising her role as Cat Valentine. The series' plot centers on the girls becoming roommates and starting their own babysitting business.
In June 2008, McCurdy announced on her official website that she was working on her debut album. The first single, "So Close", was released on March 10, 2009. The second single, "Homeless Heart", was released on May 19. The song was released in honor of McCurdy's recently deceased friend Cody Waters, who died at the age of 9 from brain cancer, and 20% of the proceeds were donated to the Cody Waters Foundation. She met Waters through St. Jude Children's Research Hospital. In mid-2009, McCurdy signed with country music label Capitol Records Nashville. On April 16, 2010, samples of select songs from McCurdy's upcoming debut country album were released online. The song clips were released in order for fans to vote for which one they believed should be McCurdy's first single. "Not That Far Away" received the most votes, and was released to country radio on May 24, 2010 and iTunes shortly after on June 1.
Capitol Nashville released an EP on August 17, 2010 which included "Not That Far Away" and four new songs, "Stronger", "Put Your Arms Around Someone", and "Break Your Heart". The iTunes version included "Me with You" as a bonus track. "Stronger" was later included on Now That's What I Call Music! Vol. 35, released on August 31, 2010. McCurdy's second single, "Generation Love", was released as a digital download on March 22, 2011, followed by its release to radio April 25, 2011. Capitol Nashville released McCurdy's self-named-seven-track extended play on February 8, 2012 at clothing retailer Justice. The full length 10-track edition was released to iTunes on June 5, 2012 and is her first full-length album.
On July 11, 2012, Fanlala released an interview with McCurdy in which she confirmed that she has since left Capitol Records Nashville, saying "I’m kind of between projects right now. I actually just left Capitol Records recently. I’m really just deciding what else I want to do next. Right now I’m working on my new show, and I’m just figuring out where I should take my music from here." On July 31, 2012, How To Rock released an interview with McCurdy, in which she talked about her acting and music careers. A follow-up interview was released on August 8, in which McCurdy reflects on her music career.
McCurdy composed an article titled, "Off-Camera, My Mom's Fight With Cancer", that was published in the Wall Street Journal on June 11, 2011. It describes in detail, her mother Debra's on-going battle with cancer and how her family is coping with the situation. The article also features tips from McCurdy on living with such a situation.