She started her film career in 2004 with the short film "The Flame". Later, she appeared in two TV series, "War and Peace" (2007), an international co-production, and the Norwegian "Honeytrap" (2008). Her first feature film was the Lithuanian-Hungarian ironic drama "" (2010), where she played one of the main roles. This film, directed by Saulius Drunga, won the Silver George Award for the best film in the Perspectives competition at the 33rd Moscow International Film Festival. Its screenplay received the New Talent Award at the Cannes Film Festival in 2007. The actress gained popularity in Russia and abroad for her role in Anna Melikian's film "Star" (2014). Her performance of socialite Margarita was highly praised by film critics, resulting in the Best Actress Award at the 25th Sochi Open Russian Film Festival (2014), a Golden Eagle Award for Best Supporting Actress (2015) as well as Nika Award and White Elephant Award nominations in the categories Best Actress and Discovery of the Year (both 2015). Following the success in Sochi, Severija Janušauskaitė participated as a jury member in the 15th . The following years were characterized by growing critical and public acclaim. In 2013 and 2015, she was nominated for the Best Lithuanian Actress Award at Vilnius International Film Festival. Her performances in the TV series "Godfather" (2014) and films such as "The Norseman" (2015) and "Dreamfish" (2016) were also widely covered by the news media. The latter film participated in the competition of the 27th Kinotavr Film Festival in Sochi and was nominated for the Russian Guild of Film Critics Award in the category Best Debut Film (2016). For her role of the mermaid Helena in "Dreamfish", Janušauskaitė received the Best Actress Award at the . She was nominated for the national film award of Lithuania, the , in 2017 in the category Best Supporting Actress for her role in the historical drama film "Emilia" (2016). In 2017, Severija Janušauskaitė became known to a broad audience in Russia and Germany thanks to her roles in major television films. In Russia, the actress is currently widely associated with her performance as Ruta Blaumane, chief of an analytical group in the Soviet Ministry of Foreign Affairs in the 1960s, in Alexey Popogrebsky's historical drama "" screened on Russia-1 TV channel in April.