Ludwig began his career at the age of nine when he featured in a Harry Potter toy commercial, a job that enabled him to sign on with an agent and obtain more commercial work. Later he was cast in movies such as
Air Bud: World Pup (2000),
MXP: Most Extreme Primate (2003),
Scary Godmother: The Revenge of Jimmy (2005),
Eve and the Fire Horse (2005),
The Sandlot: Heading Home (2007). In addition to cinema, Ludwig has also worked in television. He has performed in movies made for television, such as
A Little Thing Called Murder (2006), and television series such as
The Dead Zone. Ludwig was in
Grown Ups 2 with Adam Sandler. Ludwig's next lead role came in the part of Seth – one half of a teenage, alien brother-sister duo – in the film production of
Race to Witch Mountain (2009), also starring
Dwayne Johnson. Seth is the part originated by
Ike Eisenmann in the 1975 original,
Escape to Witch Mountain. The film opened at number one at the box office the weekend that it premiered, with receipts estimated at
$25 million. Despite his early casting success with
The Seeker, Ludwig indicated in an interview that it was his intention to attend university. In the movie adaptation of
The Hunger Games, Ludwig played Cato, the fierce male tribute from District 2, the primary threat to the protagonists' lives during the 74th Hunger Games. The film was released worldwide on March 23, 2012. Ludwig won the award for Best Fight on
2012 MTV Movie Awards along with
Jennifer Lawrence and
Josh Hutcherson, as well as the award for Best Villain at the
2012 Teen Choice Awards. Ludwig released his first single "Liv It Up (Teenage Wasteland)" on March 1, 2012. In 2013, he co-starred in the films
Lone Survivor and
Grown Ups 2. In 2014, he became a part of the main cast of the popular TV series
Vikings, playing the character of
Björn Ironside, the son of Ragnar Lothbrok and Lagertha. In 2015, he had the male lead in both the horror films
Final Girl and
The Final Girls, which are unrelated to each other. He played the pacifist hacker Dorn in 2020's
Bad Boys for Life, and also appeared in
The Band Perry's music video for "
Gentle on My Mind" alongside
Teen Wolf actress
Shelley Hennig. Ludwig signed with the country music label
BBR Music Group/
BMG in May 2021. His self-titled EP was released on May 21, 2021. On August 18, 2022, it was announced that Ludwig would appear in
Nicki Minaj's music video for her single
Super Freaky Girl. On August 26, 2022, Ludwig released his debut album
Highway 99. ==Personal life==