Groban debuted as a singer in seventh grade, but soon put it on hold for a few years. "I enjoyed the arts aspects, but my grades were slipping. I didn't feel that I was getting enough creative input. So I went to Bridges Academy to get my grades up to straight A's." While at Bridges Academy, Groban took normal classes from 9:00 AM until 1:00 PM, and then afterwards attended theater classes. He also played the penny whistle as well as the kazoo in grade school.

In 1997 and 1998, Groban attended the Interlochen Arts Camp in Michigan, majoring in musical theater, which is also when he began taking voice lessons outside of school. "I started taking music lessons on the side. I was very much into musical theater. I had a pretty good baritone voice, so I began acting and singing in school productions".

In late 1998, the 17-year-old Groban was introduced by his vocal coach to Grammy-winning producer/arranger David Foster. Groban worked for Foster as a rehearsal singer on a series of high-profile events, including the 1999 Grammy Awards -- where, as a stand-in for Andrea Bocelli, he rehearsed Foster's "The Prayer" with Céline Dion -- and the January 1999 inauguration of Gray Davis as governor of California.

Groban attended the Los Angeles County High School for the Arts as a theater major and graduated in 1999 and then attended Carnegie Mellon University in Pittsburgh, Pennsylvania, studying drama.

Groban left Carnegie Mellon after only one year when he was offered a recording contract at Warner Bros. Records through Foster's 143 Records imprint. With regard to signing Groban, Foster said: "I love his natural ability in the pop and rock arena, but I love his sense of classics even more. He's a true musical force to be reckoned with." Therefore, under Foster's influence, Groban's first album focused more on the classics with songs such as "Gira Con Me" and "Alla Luce Del Sole," the first ones decided on by Foster and Groban.

Soon after being picked up by Foster, Groban went on to perform "There For Me" with Sarah Brightman on her 2000-2001 La Luna Tour, featured on her "La Luna" Concert DVD. He made his recording debut by singing "For Always" with Lara Fabian on the movie soundtrack to A.I.: Artificial Intelligence (2001). Groban also became involved in many benefit shows, including the following: "The Andre Agassi Grand Slam Event For Children", singing alongside Elton John, Stevie Wonder, Don Henley and Robin Williams; "Muhammad Ali's Fight Night Foundation" which honored Michael J. Fox and others; "The Family Celebration" (2001) which was co-hosted by President Bill Clinton and his wife, Hillary Rodham Clinton, and David E. Kelley and his wife, Michelle Pfeiffer; and Michael Milken's CapCure event, which raises funds for cancer research.

Groban played the role of Malcolm Wyatt in the May 2001 season finale of the television series Ally McBeal, performing "You're Still You." The series creator, David E. Kelley, was impressed at Groban's performance at The Family Celebration event, and, based on the audience reaction to Groban's singing, Kelley created a character for Groban in this finale. The character of Malcolm Wyatt was so popular, with 8,000 emails from fans, that Groban was asked to return the next season to reprise his role and perform "To Where You Are."

The singer's eponymous debut album Josh Groban was released on November 20, 2001. Over the next year, it went from gold to double-platinum.

On February 24, 2002, Groban performed "The Prayer" with Charlotte Church at the closing ceremonies of the Winter Olympics, and by November, he had his own PBS special, Josh Groban In Concert (2002). In December he performed "To Where You Are" and then sang "The Prayer" in a duet with Sissel Kyrkjebø at the Nobel Peace Prize Concert in Oslo, Norway. He then joined The Corrs, Ronan Keating, Sting, Lionel Richie and others for a Christmas performance at the Vatican in Rome, Italy. In 2003, Groban performed at the David Foster created concert for World Children's Day. He performed "The Prayer" with Celine Dion and the finale song, "Aren't They All Our Children" with artists like Yolanda Adams, Nick Carter, Enrique Iglesias and Celine Dion.

Groban's second album Closer, also produced by Foster, was released on November 11, 2003. Groban said that he believed that this second album was a better reflection of him and that his audience would be able to get a better idea of him personally from listening to it. "What most people know about me, they know through my music. This time, I've tried to open that door as wide as possible. These songs are a giant step closer to who I really am and what my music is all about. Hence the title."

Two months after Closer was released, it rose on the Billboard charts from number 11 to number one. His cover of Brian Kennedy's "You Raise Me Up" became very popular on the adult contemporary charts. Groban also performed the song "Remember" (with Tanja Tzarovska) on the Troy soundtrack, "Believe" on the soundtrack to the 2004 animated film The Polar Express, and a cover of Linkin Park's "My December".

During the summer of 2004, Groban returned to Interlochen, where he gave a performance to local residents and campers, also speaking about his experiences as a young performer. On November 30, 2004, his second live DVD, Live At The Greek, was released. It also ran as a Great Performances special on PBS. Also in 2004 , Groban performed "Remember When It Rained," backed by a full orchestra, at the American Music Awards where he was nominated for Favorite Male Artist in the pop category. Groban and his recordings were nominated for more than a dozen awards in 2004, including the American Music Award, World Music Award, Academy Award, and a Grammy.

Other appearances have included The Oprah Winfrey Show, The Ellen Degeneres Show, Jay Leno, Larry King Live, The Rosie O'Donnell Show, 20/20, The Today Show, Macy's Thanksgiving Day Parade, Super Bowl XXXVIII, the Walt Disney World Christmas Day Parade, and the Rockefeller Tree Lighting.

During the first week of September 2006, Groban's latest single entitled "You Are Loved (Don't Give Up)", was exclusively released to AOL's First Listen. It was taken from his third studio album Awake, which was officially released on November 7, 2006. Josh Groban performed "You Are Loved (Don't Give Up)" as well as two other tracks from "Awake" at his recording session for Live from Abbey Road at Abbey Road Studios on 26 October, 2006. On this album Groban also collaborated with British musician and songwriter Imogen Heap, on the single "Now or Never". Two tracks were performed with the South African group Ladysmith Black Mambazo, namely "Lullaby" and "Weeping", both songs having strong African influences. Groban toured with Angelique Kidjo around the U.S. for his Awake tour. The latter also featured a performance by another famous South African artist, Vusi Mahlasela. Groban's "Awake" world tour visited 71 cities between February and August 2007, and travelled further to Australia in September and the Philippines with Lani Misalucha as his special guest in October of 2007. He did a duet with Barbra Streisand ("All I Know of Love") and also in 2007 a duet with Mireille Mathieu ("Over the Rainbow"). Groban has expressed an interest in performing on Broadway one day.

In June 2007, Josh spent some weeks in London recording a Christmas album with the London Philharmonic and the African Children's Choir, which he discussed on the DVD from "The Making of Noël". It was released on October 9, 2007 and is titled Noël. The album has been highly successful in the U.S. breaking numerous records for a Christmas album, as well as becoming the best selling album of 2007 in only its tenth week of release, at sales of 3.6 million. On 10 February, he performed at the 2008 Grammy Awards with Andrea Bocelli in a tribute to Luciano Pavarotti.

According to an advertisement that came with the CD/DVD version of Noël, "Awake Live (CD + DVD)" will be available in early 2008. According to the fan club "Friends of Josh Groban," there will be a special fan club only edition. The concert was filmed on August 28, 2007, in Salt Lake City, Utah, in honor of his first arena concert, which was given at the same city."

Also in early 2008 he took part in the Jimmy Kimmel video, "I'm F**king Ben Affleck.

Groban joined Idina Menzel on April 14th for a PBS Soundstage Taping. The day following he held his own small concert to be taped for PBS at the Rose Hall in NYC.