[5][6] Routh grew up in Norwalk, approximately 100 miles (160 km) south of Woolstock, the birthplace of George Reeves, the first actor to play Superman on television.

[2] Routh has said he was often told that he bore a physical resemblance to Christopher Reeve, who had previously portrayed Superman in a film series.

[8] In 1999, Routh left the university and moved to Manhattan and then Los Angeles, where he pursued a full-time acting career, first appearing as an extra in Christina Aguilera's 1999 music video for "What a Girl Wants".

Prior to Routh's casting as Superman in the film Superman Returns, Warner Bros. had spent over a decade developing a plan to relaunch the franchise, entitled Superman Flyby, with possible stars including actors such as Nicolas Cage, Josh Hartnett, Brendan Fraser, Tom Welling (who previously played a younger version of Clark Kent in the 2001–2011 TV series Smallville), Paul Walker, Henry Cavill (who eventually became Superman in the 2013 film Man of Steel), James Marsden (who would go on to play Lois Lane's fiancée in the film), Ashton Kutcher, Keanu Reeves, Will Smith, Johnny Depp and James Caviezel,[10] and planned directors including Tim Burton, Wolfgang Petersen, McG, Brett Ratner, and Shekhar Kapur.

[10] Singer, who has since stated that Routh was the embodiment of "our collective memory of Superman,"[11] was impressed by Routh's resemblance to the comic book icon and found the actor's humble Midwestern roots perfect for the role, as well as his "combination of vulnerability and confidence", which Singer said reminded him of Christopher Reeve.

[12] Routh was signed on to appear in two potential sequels, but due to mediocre box office results those never materialized.

Reviews of Routh's performance were generally positive, with Newsweek noting he "effortlessly lays claim to the iconic role.

Routh appeared in the independent drama Fling (formerly titled Lie to Me) (2008), co-starring his wife Courtney Ford, and the ensemble film Life is Hot in Cracktown (2009).

In 2012, Routh starred in David Kohan and Max Mutchnick's CBS half-hour, multicamera comedy series, Partners.

He played Michael Urie's character's steady partner, alongside David Krumholtz and his Table for Three co-star Sophia Bush.

That same year, he starred in the Hallmark Channel's Christmas-themed romantic comedy The Nine Lives of Christmas, which drew good reviews and high ratings.

[21] In January 2015, Arrow's co-creator and executive producer Greg Berlanti stated that they were in the midst of "very early" preliminary talks for an additional spin-off series centered on Ray Palmer/The Atom.

[22][23] In the superhero series Legends of Tomorrow (2016–2022), Routh co-starred as The Atom, along with Arthur Darvill, Wentworth Miller, Victor Garber, and Caity Lotz.

[24] Routh reprised his role as Clark Kent / Superman in the 2019–2020 Arrowverse crossover "Crisis on Infinite Earths",[25] affected by events adapted from the Kingdom Come storyline.

That same year, Routh reprised his role as Todd Ingram in the Netflix animated series Scott Pilgrim Takes Off.

On August 23, 2006, Brandon became engaged to his girlfriend of three years, actress Courtney Ford;[33] the couple married on November 24, 2007, at the El Capitan Ranch in Santa Barbara.

[37] During the 2008 Presidential election, Routh spoke at an Iowa rally in support of Democratic candidate Barack Obama.