Through the late 1990s, Mortensen played supporting roles in a variety of films including the historical romance The Portrait of a Lady (1996), the action drama G.I.

He later starred in several David Cronenberg films including A History of Violence (2005), Eastern Promises (2007), for which he was nominated for the Academy Award for Best Actor, and A Dangerous Method (2011).

[4] He gained additional Academy Award nominations for his leading roles as an anarchist father in Captain Fantastic (2016) and as Tony Lip in Green Book (2018).

In addition to film, Mortensen has pursued a variety of artistic endeavors including painting, poetry, music, and photography.

Mortensen composed and performed music for films including The Lord of the Rings soundtrack, and has collaborated with guitarist Buckethead on several albums.

Mortensen attended primary school and acquired a fluent proficiency in Spanish while his father managed poultry farms and ranches.

The play, which revolves around homosexual prisoners in a concentration camp in Nazi Germany, was known for the leading performance by Ian McKellen,[21] with whom Mortensen later costarred in the film trilogy The Lord of the Rings.

Mortensen made three film appearances in 1990: Edward "Tex" Sawyer, a member of a cannibalistic family in Leatherface: The Texas Chainsaw Massacre III, John W. Poe in Young Guns II, and Cameron Dove, a military veteran suffering from radiation poisoning in The Reflecting Skin.

Although Ruby Cairo was Mortensen's highest-budget film at this point in his career, it was a commercial failure, bringing in only 608,000 on its 24 million dollar budget.

[28] He also acted in Crimson Tide, Daylight, A Walk on the Moon, The Passion of Darkly Noon, 28 Days, and The Prophecy, with Christopher Walken.

[30] Although the film earned his co-star, Demi Moore, a Golden Raspberry Award for her role, Mortensen's performance as Command Master Chief John James 'Jack' Urgayle was favorably received.

At one point during filming of The Two Towers, Mortensen, Orlando Bloom, and Brett Beattie (stunt double for John Rhys-Davies) all had painful injuries, which led to Peter Jackson jokingly referring to the three as "the walking wounded.

"[34] Also, according to the Special Extended Edition DVD of The Lord of the Rings: The Return of the King, Mortensen purchased the two horses, Uraeus and Kenny, whom he had ridden and bonded with over the duration of the films.

Mortensen starred in David Cronenberg's 2005 film A History of Violence as a family man revealed to have had an unsavory previous career.

[37] In the DVD extras for A History of Violence, Cronenberg related that Mortensen is the only actor he had come across who would come back from weekends with his family with items he had bought to use as props on the set.

Later that year, he joined the cast of The Road, a film adaptation of the Cormac McCarthy novel of the same name,[44] and collaborated with David Cronenberg for a third time on A Dangerous Method.

He's a tough but adoring father, a grieving widower and a passionate defender of his wife's final wishes, and Mortensen plays all these notes, and more with subtlety and grace".

Mortensen portrayed Tony Lip, an Italian-American bouncer hired to drive and protect pianist Don Shirley (Mahershala Ali) on a tour through the Jim Crow South from 1962 to 1963.

[52] In 2020, Mortensen released his directorial debut Falling, which he also wrote, produced, composed the score for and starred in alongside Lance Henriksen at the Sundance Film Festival.

[55] During the COVID-19 pandemic in May 2020, Mortensen along with fellow Lord of the Rings actors Sean Astin, Sean Bean, Orlando Bloom, Billy Boyd, Ian McKellen, Dominic Monaghan, Miranda Otto, John Rhys-Davies, Andy Serkis, Liv Tyler, Karl Urban, Elijah Wood, writer Philippa Boyens, and director Peter Jackson joined actor Josh Gad's YouTube series Reunited Apart, which reunites the cast of popular movies through video-conferencing, and promotes donations to non-profit charities.

[56] Mortensen was cast as British cave diver Rick Stanton in the biographical film Thirteen Lives directed by Ron Howard which was released in July 2022.

[60] Mortensen and Caleb Landry Jones will star together in the Vietnam War thriller Two Wolves which will be directed by documentary filmmaker Alex Gibney.

[64] Perceval Press is also the home of Mortensen's many personal artistic projects in the area of fine arts, photography, poetry, song, and literature.

With anthropologists Federico Bossert and Diego Villar, he has written several works related to ethnography of natives in South America,[66] specifically in Argentina, Brazil, Paraguay, and Uruguay.

The finished product included a guitar part by Buckethead, which caught Viggo's ear and led him to initiate contact with the guitarist.

[88] Mortensen has talked about his family's struggles with dementia, seeing both of his parents, three of his four grandparents, aunts, uncles, and his stepfather battle the condition.

[98] He is also a fan of the New York Mets and, in an interview promoting 2009 film The Road, was seen wearing apparel indicating his support for the Australian Football League's Collingwood Magpies.

"[101] In 2009, Mortensen signed a protest stating that the Toronto International Film Festival's "Spotlight on Tel Aviv" program implicitly condoned the Israeli occupation and marginalization of Palestinians.

[108] After Vox, a far-right Spanish party, published a tweet depicting Mortensen as Aragorn fighting various social movements, including pro-Catalan separatists, during the campaign for the 2019 Spanish general election, Mortensen wrote a letter to the editor criticizing the depiction saying, "Not only is it absurd that I, the actor who embodied this character... and a person interested in the rich variety of cultures and languages that exist in Spain and the world, is linked to an ultra-nationalist and neo-fascist political party, it is even more ridiculous to use the character of Aragorn, a polyglot statesman who advocates knowledge and inclusion of the diverse races, customs and languages of Middle Earth, to legitimize an anti-immigrant, anti-feminist and Islamophobic political group.

His portrayal of Aragorn in The Lord of the Rings trilogy earned him nominations for the SAG Award for Outstanding Cast, winning for the final installment The Return of the King (2003).