Karl later entered the Roll Call freestyle competition on Los Angeles radio station Power 106, where he lasted a record 45 days on air to become the show's all-time champion. Karl created a demo exhibiting his satirical style and tightly-wound rhymes. He eventually signed with Interscope Records for almost a million dollars, where he recorded what was to be his debut album, Your Housekeeper Hates You, which included guest appearances by Redman, Kanye West, will.i.am, DJ Quik, Fabolous, Mýa, Sugar Ray, DJ Clue and MC Serch. However, Interscope informed Karl that his album could not be commercially released due to scheduling conflicts and he decided to leave Interscope. Jensen released his memoir, Kanye West Owes Me $300 (and other true stories from a white rapper who ALMOST made it big) detailing the entire experience in June 2016 with Crown Books.
Karl's music was featured in the video game NBA Live 2003, a game in which he was also a hidden character. His song, "Back/Forth," was also featured in the 2009 movie It's Complicated. Karl also appeared on season 2 of Burning Love on Yahoo & E! and battled Martin Starr as part of the show. He currently manages Nova Rockafeller, a Canadian rapper on Boardwalk/Mercury records.
In 2016, Karl recorded a free song named "Like Riding A Bike" available on soundcloud featuring Mike Shinoda from Linkin Park. He also started a sketch on The Late Late Show with James Corden called Drop The Mic, where Corden goes head to head battle rapping a different celebrity each installment. After episodes with Anne Hathaway, Kevin Hart, David Schwimmer and Usain Bolt, TBS bought the concept and will air 16 episodes starting in 2017. Karp will act as Executive Producer and writer.
Karp co-owns and operates Gallery 1988, two pop-art focused galleries in Los Angeles, California both located on Melrose Avenue. He co-wrote the book Just Can't Get Enough for Abrams Books with Matthew Robinson. Gallery 1988 is well known for its Kevin Smith hosted annual show, Crazy 4 Cult, where 100 artists reinterpret classic cult movies in their own style. At one time, Karp was also the brand manager and designer for Pete Wentz's Clandestine Industries. His marketing company, Tyson/Givens Design & Marketing created the LOST Underground Art Project for the show's final season and worked with the TV show Breaking Bad The gallery has also hosted exhibits for movies including The Avengers, Rick & Morty  and Star Wars: The Force Awakens.
Karp was a host on a podcast called Hype Men in which he, Eric Rosenthal and Jeff Rosenthal, aka Itsthereal, discussed hip-hop. It was started in August 2010 and ran until July 2011.
He hosts a show on Earwolf called Get Up On This in which he, Matthew Robinson and a guest discuss things they think will soon become popular. The show moved to the Wolfpop network from SModcast Internet Radio (S.I.R.). The show is released as a Podcast on the Earwolf network and iTunes.
He is a frequent guest on Pistol Shrimps Radio, a podcast on Earwolf following a women's recreational league basketball team in Los Angeles. In the halftime "Sock Report" segment, Karp discusses the socks of Pistol Shrimps and opposing players. In the second season of Pistol Shrimps Radio, Karp's character changed to "Greg Escalante," who later revealed he was Jensen Karp hiding from the Church of Scientology. He also hosts a podcast with his mother where she gives love advice to listeners called Motherly Love.
Karp appeared on The Howard Stern Show in 2011 to talk about his time in the rap industry and perform The Roll Call with Howard & Lisa G. He also acted as the Creative Director at comedy YouTube Channel, Jash, where he produced and wrote on projects like The ArScheerio Paul Show & the Chance The Rapper music video for "Na Na.". He also appeared on Season 1 of VH1's Barely Famous playing Erin Foster's boyfriend and was seen numerous times on the final season of Candidly Nicole. Karp also appeared on Comedy Central's @Midnight. He has written for Rolling Stone, the ESPYs, the MTV Movie and Video Awards, The Late Late Show with James Corden and Funny Or Die.
- Just Can't Get Enough (2007) Co-written with Matthew Robinson
- Kanye West Owes Me $300: And Other True Stories from a White Rapper Who Almost Made It Big (2016)
- Leeds, Jeff (2002-11-11). "No Rap on Eminem: He Gets His Shot, His Opportunity, and Doesn't Let It Slip: Record labels trying to duplicate Eminem's cross-racial success are finding it difficult to make a connection with rap audiences". Los Angeles Times. p. A1.
- Stirling, Stephen (2006-01-09). "Hot Karl: The Great Escape". PopMatters. Retrieved 2008-06-25.
- Clippers 2013
- Like Riding A Bike
- "About Us - Gallery 1988". nineteeneightyeight.com. Retrieved June 11, 2015.
- http://damoncarltonandapolarbear.com/dcpb/ DamonCarltonAndAPolarBear.com
- MARVEL'S THE AVENGERS FEATURED AT GALLERY1988
- Cool Stuff: Gallery1988’s Art Awakens Star Wars Art Show