Lerman has stated that he had a passion for movies from a young age.^[6][12] He appeared in commercials in the 1990s,^[14] and subsequently made his film debut in 2000's The Patriot, playing William Martin, one of the children of Mel Gibson's character. The same year, he co-starred with Gibson again in What Women Want, playing Gibson's character as a child. Lerman's next feature film roles were in 2001's Riding in Cars with Boys and the 2004 thriller The Butterfly Effect, portraying younger versions of characters played by Adam Garcia (in the former film) and Ashton Kutcher (in the latter).^[15]

Lerman's role in the 2003 made-for-television film A Painted House won him a Young Artist Award for Best Performance by a Leading Young Actor in a television production.^[16] In 2004, he was cast in the television series, Jack & Bobby, playing the title role of Robert "Bobby" McCallister, who was destined to become President of the United States. The show ran on The WB Television Networkduring the 2004–2005 season, and was subsequently canceled, though Lerman won another Young Artist Award for his performance.^[17][18]

Continuing his film work, Lerman played the lead role of Roy Eberhardt in the children's adventure Hoot. The film opened on May 5, 2006, and won him a third Young Artist Award, this time for Best Performance in a Feature Film - Leading Young Actor (2007).^[19] In 2007, Lerman appeared in The Number 23, in which he played Robin Sparrow, the son of Jim Carrey's character, Walter Sparrow. That year, he also appeared in the critically acclaimed western 3:10 to Yuma, where he played William Evans, the son of Christian Bale's character; Lerman received positive reviews for his role,^[20] and was again nominated for the Young Artist Award - Best Performance in a Feature Film - Leading Young Actor (2008). It was the second consecutive year he received a nomination in that category, although this time he did not win.^[21][22]

In 2008, Lerman co-starred in Meet Bill as The Kid (his character is never referred to by name), and in 2009, he appeared in the science fiction film Gamer as Simon, a teenage gamer who controls one of the characters in a video game played with live human subjects.^[23] Also that year, Lerman had a leading role in the Renée Zellweger comedy feature My One and Only, playing a teenage version ofGeorge Hamilton - an aspiring writer who, after his parents abruptly split, accompanies his mother and brother on a cross-country trip, eventually arriving in Hollywood.^[24][11]

Lerman played Percy Jackson in the 2010 film Percy Jackson & the Olympians: The Lightning Thief, based on the book by Rick Riordan.^[25] He was not familiar with the book series when he received the script for the film.^[6] Regarding the similarities between Lerman's character and Harry Potter, Lerman told an interviewer: "Honestly, my character doesn't have much in common with Harry Potter besides the fact that he's an unlikely hero who's thrown into a huge situation".^[7] Lerman is signed to appear in two more Percy Jackson films, and has stated that he would like to star in adaptations of all five books in the series.^[6][26] Also in 2010, Lerman appeared in "Change the Odds", a public service announcement video for the Stand Up to Cancer charity; the video also featured Dakota Fanning,Zac Efron, Andrew Garfield, and other actors.^[27]

Lerman is represented by the Creative Artists Agency.^[28] He will play d'Artagnan in director Paul W. S. Anderson's 3D film version of The Three Musketeers, which was filmed from August 2010 to November 2010, and is scheduled for release on October 14, 2011.^[29] Lerman was cast in the role without having to audition,^[30] and wore hair extensions to portray his character.^[31] He will also star in a film adaptation of Stephen Chbosky's novel The Perks of Being a Wallflower, playing the lead role, Charlie; filming is scheduled to begin in the summer of 2011.^[32][33][34]

Lerman has signed on to star in The Only Living Boy in New York, an independent film written by Allan Loeb and to be directed by Seth Gordon; the story is a coming-of-age drama in which Lerman's character's father has an affair. Filming is scheduled to begin in fall 2011.^[35]

Lerman is a friend of actor Dean Collins,^[36] who played his best friend on Jack & Bobby; they remained close after the series' cancellation, and worked together again on Hoot, where Collins had a supporting role. In their spare time, the two collaborated on comedic short films. As well as acting, they wrote, directed, and shot the videos, often enlisting the help of family and friends. The shorts were uploaded to YouTube under the joint account name of "monkeynuts1069".^[37]

In 2006, Collins and Lerman formed a band, Indigo, along with musician Daniel Pashman; Collins sings lead vocals, Lerman plays keyboard and guitar, and Pashman plays the drums.^[2] Lerman also plays the piano.^[38]