Madden was born Benjamin Levi Combs on March 11, 1979, in Waldorf, Maryland, to Robin Madden and Roger Combs. He has an identical twin, Joel Madden, with whom he formed the band Good Charlotte. He has an older brother named Josh and a younger sister named Sarah. His maternal grandmother was Jewish. All attended La Plata High School in La Plata, Maryland.

In 1996 Madden started a band with his twin brother Joel named Good Charlotte.

Madden started the fashion line called Made Clothing, along with his brothers Joel and Josh, but the line became defunct. In early 2006, it became DCMA Collective. A DCMA Collective store opened in Los Angeles on March 15, 2008, but later closed.

In February 2008, Madden broke up with his long-time fiancée, Sophie Monk.

On April 3, 2010, Madden took part in a boxing match against MTV and VH1 host Riki Rachtman at Ellismania 5: Get These Brawls. The event was hosted by Jason Ellis at The Joint in the Hard Rock Hotel and Casino in Las Vegas. Madden beat Rachtman by knockout at 1 minute and 42 seconds into the first round.

On November 11, 2011, Madden and his brother Joel Madden released a free mix-tape, “The Madden Brothers: Before Volume 1”. It contains new artists the brothers were personally interested in. Their brother Josh Madden helped to produce the mix-tape. Then unknown rappers, Machine Gun Kelly, Rockie Fresh, Kreayshawn, Cassie Veggies, HXLT, and Wiz Khalifa all appeared on the mix-tape.

In 2012, Benji appeared on the TV show The Voice Australia, alongside Joel as joint mentor-judges.

In early 2013, Benji helped write Tonight Alive’s song “Breakdown”. He sang back-up vocals at the end of the song and made an appearance in the video.

In 2014, electronic dance music artist TJR released his track “Come Back Down”, which features Benji on the track’s vocals. The Madden Brothers recording “Greetings from California” was released on September 16, 2014.

Madden began dating actress Cameron Diaz in May 2014. The two were unofficially engaged before Christmas Day in 2014 and were married on January 5, 2015, in a Jewish-inspired ceremony, at their Beverly Hills home. On December 30, 2019, they had a daughter via surrogate pregnancy.

In mid-2014, both of the Madden brothers appeared as coaches on The Voice Kids Australia in a double chair, after the example of the Dutch The Voice of Holland and The Voice Kids (Netherlands season 1) edition in which the singer’s duo Nick & Simon appeared as a judging duo between 2010 and 2015. In early 2015, Benji joined Joel as a coach on the main edition of The Voice, bringing the number of coaches up to five.

In 2015 Madden and his two brothers formally started their company MDDN, of which Benji is CEO, offering artist management, artist development and creative services. The company gained success quickly with the brothers taking management of Jessie J, Sleeping with Sirens, Hollywood Undead, Waterparks, Antiflag, Chase Atlantic, K Camp, Architects and more.