Arcelus grew up in Port Washington on Long Island, New York. He attended Williams College and graduated in 1999 with a degree in political science.

Arcelus has made a career in theater on Broadway, regionally, and internationally. He began his career in the early 2000s, and spent three years working at an international business firm while auditioning and performing in amateur theater at night. He performed in a handful of small New York theater productions as well as regional productions like that of The Who’s Tommy in Newark, New Jersey in 2000 and Big River in Portsmouth, New Hampshire. He joined the repertory theater company of Weathervane Theatre in Whitefield, New Hampshire for their 2001 season; at Weathervane, he performed in productions including Floyd Collins, Cabaret, and I Love You, You’re Perfect, Now Change. Following this experience he took part in a bilingual production of West Side Story in Guatemala.

Arcelus made his Broadway debut in 2002 in Rent, first as a swing, covering the male ensemble roles as well as Mark and Roger, and then as Roger throughout the first half of 2003. He remained with Rent as a swing until Fall 2004.

Some of his first professional screen acting roles were for English-language dubs of animated TV shows. He continued to do this throughout the 2000s and voiced characters in shows including Winx Club and multiple series within the Yu-Gi-Oh! franchise. In 2004, Arcelus appeared in the movie musical Temptation, with Broadway stars Alice Ripley, Adam Pascal, and Zoe Saldana, among many others.

Arcelus married his Wicked co-star Stephanie J. Block on October 16, 2007, with a religious ceremony following on October 25, 2007 in Tuscany. Block played Elphaba in Wicked, both on the national tour and on Broadway. Their daughter Vivienne Helena Arcelus was born on January 19, 2015.

He starred as Bob Gaudio in the Broadway production of Jersey Boys from January 10, 2008 to January 11, 2009. before starring in Happiness, a musical which ran Off-Broadway at Lincoln Center Theater’s Mitzi E. Newhouse Theater for fourteen weeks beginning on February 27, 2009. He resumed the role of Bob Gaudio in the Broadway production of Jersey Boys on July 14, 2009 and finished the role on October 10, 2010.

He assumed the role of Jack Chesney in Where’s Charley? in a concert production as part of New York City Center’s Encores! series from March 17–20, 2011. From May 6 through June 19, 2011, took part in the original stage production of A Time to Kill, premiering at the Arena Stage in Washington, D.C., based on the John Grisham novel of the same name; Arcelus originated the role of Jake Brigance. Later that summer, Arcelus filmed and helped produce the independent feature film The Last Day of August, which premiered in October 2012. In November 2011, Arcelus starred in an off-Broadway limited engagement musical production of The Blue Flower at Second Stage, along with Marc Kudisch and Teal Wicks.

In 2012, Arcelus starred in the independent film The Last Day of August. Later that year, he was cast as Lucas Goodwin in the Netflix TV series House of Cards. From 2013 to 2016, he had a recurring role in the show’s first, second, and fourth seasons. In 2013, Arcelus reprised his role of Jake Brigance in the Broadway production of A Time To Kill at the Golden Theatre in New York City, which premiered on October 20, 2013.

As part of the collective The Grundleshotz, Arceus co-wrote the musical Gettin’ the Band Back Together. Following four years of improvisational rehearsals, the musical debuted regionally in 2013 at the George Street Playhouse in New Jersey before receiving a pre-Broadway workshop in 2014. The musical played on Broadway at the Belasco Theatre during Summer 2018.

In early 2014, he was cast in the Cinemax pilot Blanco. Soon after, he also joined the cast The Best of Me, based on the Nicholas Sparks novel of the same name.

In 2014, he began portraying Jay Whitman on the CBS drama Madam Secretary. After having a recurring role during the first two seasons of the show, Arcelus became part of the main cast for the final four seasons of the show; he acted in one hundred episodes before the series concluded in December 2019.

Since 2014, Arcelus has also had small roles in the films Ted 2 (2015) and Split (2016), as well as guest roles in shows including The Leftovers, FBI, and Bull. He joined the cast of the Steve McQueen miniseries Codes of Conduct, which was given a limited series order by HBO in 2015. The project was ultimately scrapped by the network the following year. In 2016, Arcelus had a six-episode arc in HBO’s The Deuce.