Bryan Hymel came to the attention of opera houses at the age of 19, when he was a winner in the Verdi Aria Competition at the Aspen Music Festival in Aspen, Colorado. A year later he was a grand finalist in the Metropolitan Opera National Council Auditions—where he was the youngest participant—and he received an encouragement grant from the George London Foundation for Singers. After graduating from Loyola University New Orleans with a Bachelor's degree in Vocal Performance, he participated in the Merola Opera Program at the San Francisco Opera. Following his time there he attended the prestigious Academy of Vocal Arts in Philadelphia, where he was further able to hone his craft.
Hymel made his professional debut in 1998 as the Philistine messenger in Samson et Dalila with the New Orleans Opera, a company where he has performed many roles, including Arturo in Lucia di Lammermoor, Luigi in Il tabarro, and Rinuccio in Gianni Schicchi. After his hometown debut, Hymel sang Tamino in Die Zauberflöte and the Duke in Rigoletto with Opera Grand Rapids. He made his European debut in 2007 at the Wexford Festival Opera, performing the role of the Prince in Dvorak’s Rusalka. Later that year he made his New York recital debut with Michelle DeYoung under the sponsorship of the George London Foundation. He has also sung at Carnegie Hall with Opera Orchestra of New York in a gala concert honoring the 100th performance there of Eve Queler that also featured Renée Fleming, Marcello Giordani, and Dolora Zajick.
In recent years Hymel has been seen in many leading opera houses in Europe as well as North and South America, performing Don José in Carmen at the Royal Opera House, Covent Garden, the Canadian Opera Company, with the Simon Bolivar Orchestra in Caracas, Venezuela, conducted by Sir Simon Rattle, and at La Scala Milan. He has also sung the role of Pinkerton in Madama Butterfly with English National Opera and the Canadian Opera Company, Cavaradossi in Tosca with Opéra National de Bordeaux, Guido in A Florentine Tragedy and Arturo in I Puritani with Greek National Opera, Énée in Les Troyens with the Netherlands Opera, and the Prince in Rusalka with the Boston Lyric Opera. In the summer of 2011, Hymel sang the title role in Faust at The Santa Fe Opera. 
In July 2012, Hymel performed the role of Énée in the Covent Garden Troyens, replacing Jonas Kaufmann who was suffering from an infection., and replaced Marcello Giordani in the same role for his Metropolitan Opera debut on December 26, 2012, as well as all subsequent performances in the 2012/2013 season, including a worldwide HD telecast.
In November 2014 Hymel sung the role of Polyeucte in a concert performance of Donizetti's 1840 opera, Les Martyrs, an adaptation into French of his 1838 Poliuto written for Naples in Italian but not performed there until 1848. It was given by the Orchestra of the Age of Enlightenment at London's Royal Festival Hall.
In 2002 Hymel was one of the winners of the Opera Lirica d’Orvieto Aria Competition in Perugia, Italy as well as the Palm Beach Opera Competition. He was the winner of the George London Award in 2007. In 2008 he had a great run of success in competitions, being named the First-Prize winner of the Giulio Gari Foundation Competition, the Loren L. Zachary Vocal Competition, and the Licia Albanese/Puccini Foundation Competition, and in 2009 he was named Top Prize Winner of the Gerda Lissner Foundation Competition. In 2012 he won the Beverly Sills Award.
- Anthony Tommasini, "OPERA REVIEW; Listening to the Future At the Met Auditions", The New York Times, March 8, 2000
- Allan Kozinn, "article title", The New York Times, March 24, 2010
- Bernard Holland, "title", The New York Times, March 8, 2008
- Neil Fisher, "Carmen at Covent Garden", The Times (London), June 10, 2010
- Christopher Holie, Opera News, April 2010
- Hymel in Faust, on santafeopera.org
- "Jonas Kaufmann withdraws from Royal Opera House Les Troyens", Gramophone (London), May 29, 2012
- Donizetti's Les Martyrs on oae.co.uk