Alexander Ludwig

Declan O'Brady in Guy Ritchie's The Covenant (2023), Bad Boys: Ride or Die (2024) and Rome Archer in Marked Men: Rule + Shaw (2025). He starred as legendary Viking Björn Ironside in the History Channel series Vikings (2014–2020) and had a lead role in the Starz drama series Heels (2021–2023).

Alexander Richard Ludwig was born in Vancouver, British Columbia, Canada, to Sharlene (née Martin), a former actress, and Harald Horst Ludwig, a businessman and former co-chair of Lionsgate Entertainment. He has three younger siblings. Ludwig was drawn to the profession, saying in an interview, "I have a big imagination. I love performing." Despite his mother's early career as an actress, Ludwig had to convince his parents to support his desire to pursue acting as a child. His parents believed that child actors "can get sucked into a life that isn't reality." They prioritized education, and so he attended regular school while pursuing his acting dreams. "It was definitely challenging to juggle school while filming," he reflected in the same interview. "My school wasn't used to it, and I wasn't used to it. It was the most amazing experience, but it was really hard." Ludwig studied at the University of Southern California (but left before graduating), where he was in the Phi Kappa Psi fraternity.

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 obtained his leading role in The Seeker: The Dark Is Rising (2007) after a "gruelling audition process." By his count, he had 16 auditions before being cast. 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 another interview, the actor said that the most challenging thing about filming The Seeker was trying "to juggle school while filming." He stated: "My school wasn't used to it, and I wasn't used to it. It was the most amazing experience, but it was really hard." 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.

Ludwig was a competitive freestyle skier, and has participated in skydiving. In February 2019, Ludwig disclosed issues he experienced with depression, anxiety, alcoholism, and substance abuse starting at the age of 14. In 2020, he married Lauren Dear. After suffering three miscarriages, Dear gave birth to their first child, a daughter, on April 27, 2023. They had a second child, a son, on June 12, 2024.