Bieber has cited Chris Brown, Michael Jackson, the Beatles, Boyz II Men, Justin Timberlake, Stevie Wonder, Tupac, Usher and Kanye West as his musical inspirations. In 2012, Bieber said, "music is music, and I'm definitely influenced by Michael Jackson and Boyz II Men and people who were black artists—that's what I like." Believe was influenced by Timberlake, for which Bieber was trying to "create a new sound that people aren't really used to hearing ... like when Timberlake did FutureSex/LoveSounds: It was a new sound... acoustic guitar over hard drums."

Bieber incorporates a variety of genres in his music, focusing mainly on pop, and occasionally dance-pop or EDM. In 2010, Jody Rosen of Rolling Stone asserted that the content of his music was "offering a gentle introduction to the mysteries and heartaches of adolescence: songs flushed with romance but notably free of sex itself". During the initial years of his career, his musical style was noted for being aimed to a more teen pop and "bubblegum-ish" direction.

In January 2012, Bieber told V magazine: "I want to do it at my own pace. I don't want to start singing about things like sex, drugs and swearing. I'm into love, and maybe I'll get more into making love when I'm older. But I want to be someone who is respected by everybody." But since then, Bieber gradually altered his artistry, with Peter Gicas of E! Online describing "PYD" as "sexed-up", while In Touch Weekly magazine said that his song with Maejor Ali and Juicy J "Lolly" might make his fans a bit uncomfortable because of its lyrics that refer to oral sex. In 2015 Bieber released the EDM-fuelled album, Purpose, where he collaborated with Skrillex, and explored serious themes such as "life experiences", through "feel-good music".

Bieber initially sang with a boy soprano voice, before his voice broke, as was evidenced during the debut performance of "Pray" at the 2010 American Music Awards. Sean Michaels of The Guardian described puberty as "the biggest threat to his career" at the time. Jody Rosen commented that Bieber sings with "swing and rhythmic dexterity" on his debut album, noting his tone to be "nasal".

Bieber started to receive voice coaching from Jan Smith in 2008. As an adult singer, Bieber's voice type is tenor, with a vocal range spanning from the baritone A2 to the high tenor F5. In a review of his Purpose album, Neil McCormick of The Daily Telegraph complimented his "soft, supple and seductive singing". Caroline Sullivan of The Guardian also praised Bieber's "affectedly breathy voice", noting that "the voice soon palls, but the songs are often interesting.

Throughout his career, Bieber has sold an estimated 150 million records worldwide, making him one of the best-selling music artists of all time.

In 2011, Bieber was honoured with a star in front of Avon Theater in Stratford, Ontario, Canada, where he used to busk when he was younger. On November 23, 2012, Bieber was presented with the Queen Elizabeth II Diamond Jubilee Medal by the former Prime Minister of Canada, Stephen Harper. He was one of 60,000 Canadians to receive the Diamond Jubilee medal that year. In 2013, Bieber received a Diamond award from the Recording Industry Association of America (RIAA) for his single "Baby", which at the time became the highest-certified digital single of all time. Bieber is credited with four Diamond certifications from the RIAA. Bieber has won two Grammy Awards out of 23 nominations, one Latin Grammy Award, eight Juno Awards, two Brit Awards, 26 Billboard Music Awards, 22 ASCAP Awards, and numerous fan voted accolades which include 18 American Music Awards, 23 Teen Choice Awards (the most wins for a male individual), eight iHeartRadio Music Awards, and six MTV Video Music Awards. He has also won a record 22 MTV Europe Music Awards out of a record 52 nominations (the most for any artist). At age 19, Bieber received the Milestone Award at the 2013 Billboard Music Awards in recognition for breaking boundaries with his creativity and contribution to the musical landscape, surpassing the likes of Taylor Swift and Bruno Mars to the award. All of Bieber's studio projects are certified Platinum or higher by the RIAA and have received numerous accolades. He is the youngest (27) solo artist to have eight US number-one albums, a record held by Elvis Presley since 1965. Bieber is the first artist in Spotify history to have 15 songs surpass 1 billion streams.