Eventually, he joined the group Barracuda and toured with the band for two years. In 1996, he released his debut instrumental album titled, Addiction to the Friction. In 1998, Ashba joined BulletBoys as part of the band's new lineup. It was during his time with the band that he met Joe Lesté of Bang Tango. In 1999, he departed the group to start a new band with Lesté.

In 1999, Ashba began piecing together the band that would become Beautiful Creatures with Bang Tango frontman Joe Lesté. They added former Shake The Faith and No. 9 Bassist Kenny Kweens and session Drummer Anthony Focx, who performed in the 1992 film Wayne's World appearing as the Drummer in Tia Carrere's club band. Focx became the group's second Guitarist and Glen Sobel, another session Drummer, was brought in to take over drums. This was the first lineup under the moniker Beautiful Creatures. Prior to naming, the band opened one show in Houston, Texas for Kiss during their reunion tour after Ted Nugent pulled out. The band then signed with Warner Bros. and released their self-titled debut Beautiful Creatures, produced by Marilyn Manson cohort Sean Beavan, on August 14, 2001. Album track 1 A.M. was featured in the Soundtrack for the 2001 horror film Valentine and TV series Smallville. Ride was featured on the Soundtrack to the 2002 remake of Rollerball. Despite appearing at Ozzfest, the Rolling Rock Tour the band was dropped from their label due to poor album sales. On February 13, 2002, the band announced that Ashba had left the group and the band found a replacement and continued on.

Daren Ashba owns two corporations, Ashba Media, Inc. and Ashbaland Inc. In 2003, he founded Ashba Media, Inc. This creative agency was announced the Agency of Record for Virgin Entertainment. AMI designs the look and feel of every Virgin Megastore. They also have other clients, such as Ovation guitars, Royal Underground and many more. Ashba contributed to Mötley Crüe's 2008 album Saints of Los Angeles penning all tracks with the exception of "This Ain't a Love Song". The title track "Saints of Los Angeles" was nominated for a Grammy the same year.

In 2006 Ashba set up Funny Farms Studios with Nikki Sixx. They began writing and producing, and performing music together which included collaborations with singer Marion Raven, whom Sixx had worked with before, on her Heads Will Roll EP and album Set Me Free. James Michael also is credited on the albums. In March 2007, Sixx penned "Reason I'm Alive" for Drowning Pool's new album Full Circle with both Sixx and Ashba co-producing the track.

Ashba released the critically acclaimed album The Heroin Diaries Soundtrack after collaborating with Mötley Crüe Bassist Nikki Sixx and Producer James Michael under the name Sixx:A.M. in August, 2007 serving as a Soundtrack to Sixx's autobiography The Heroin Diaries: A Year in the Life of a Shattered Rock Star. The single "Life is Beautiful" reached #2 on the Billboard Hot Mainstream Rock Tracks. Originally the group stated they had no intention of touring. After constant support for the band and interest in a tour, they held a nationwide vote for tour dates. The tour was scheduled to start in spring 2008, but had been postponed to the summer due to unforeseeable circumstances. On April 15, 2008, Sixx:A.M. announced they would be touring as part of Mötley Crüe's Crüe Fest, along with Buckcherry, Papa Roach and Trapt. The tour began on July 1, 2008, in West Palm Beach, Florida. During Crüe Fest, Papa Roach Drummer Tony Palermo served as a touring Drummer for the band. A deluxe tour edition of The Heroin Diaries Soundtrack was released on November 25, 2008, which included a bonus live EP entitled Live Is Beautiful which features recorded performances from the band's summer tour. In April 2009, both James Michael and Nikki Sixx confirmed that the band was in the studio, recording new material. Sixx added that the new material is "inspiring. it feels like we may have topped ourselves on this album coming up, and can't wait for you to hear what it sounds like." On May 3, 2011 the Sixx:A.M. album This Is Gonna Hurt was released. In February 2018, Ashba announced that the band was on hiatus.

On March 23, 2009 Ashba was announced as the new lead Guitarist of Guns N' Roses replacing Robin Finck, who had left the band to rejoin Nine Inch Nails. He first toured with the band as part of the Chinese Democracy Tour where on December 11, 2009 Guns N' Roses played in Taiwan. He also toured with the band as part of its 2013 Australian Tour and appears on the band's 2014 Appetite for Democracy 3D video release. On July 27, 2015, DJ Ashba announced he was leaving the band, citing his commitment to his family and his other band Sixx:A.M.. Ashba released a statement saying "I have reached a point in my life where I feel it's time to dedicate myself to my band Sixx:A.M., my adoring wife and family, and to the many new adventures that the Future holds for me."

In 2013, three Las Vegas police officers took Ashba and his girlfriend Nathalia Henao on a ride in a police helicopter, ending with Ashba proposing marriage to Henao. The three police officers involved were punished by the department for improper and unauthorized use of a police vehicle. One officer retired in anticipation of demotion, one was transferred and the pilot was banned from flying for the metro police department.

As of 2016, now uses his very own Schecter DJ Ashba signature model from the Schecter USA Custom Shop.

In February 2018, Ashba announced a spin off band of Sixx:A.M., called Pyromantic. The band will feature Ashba and James Michael.