Born in 1956 in Baltimore, Karukas started playing piano at age six and experimented with drums, trumpet, and guitar. By his teens, however, he was a dedicated keyboardist taking private lessons and beginning to work professionally playing organ in R&B bands. At age 17, he embarked on a five-year stint with Tim Eyermann and the East Coast Offering. He also spent time as a studio musician in Washington, D.C. before moving to Los Angeles in 1983. There, he gained a reputation as a go-to sideman and session player, working with artists like Ronnie Laws, David Benoit, Richard Elliot, Grant Geissman, Melissa Manchester, and more. In 1986, he joined guitarist Russ Freeman as a founding member of the crossover jazz group the Rippingtons, appearing on their breakthrough Top Five jazz debut Moonlighting.
He also began leading his own groups, including a line-up that featured a young Dave Koz. Working under the name Karukas, he made his solo debut with 1987's The Nightowl. More solo albums followed, including 1990s Key Witness, 1992's Sound of Emotion, and 1993's Summerhouse. You'll Know It's Me arrived in 1995 and featured contributions from saxophonist Boney James and guitarist Ricardo Silveira. With 1998's Blue Touch Karukas gained yet wider visibility, cracking the Top 20 of Billboard Contemporary Jazz Albums chart. He followed with 2000's Nightshift and 2002's Heatwave. In 2005, he again hit the Top 20 with Looking Up. There were also sessions with artists like Kirk Whalum, Brian Bromberg, Dori Caymmi, Peter White, Phil Sheeran, Craig Chaquico, Jonathan Butler, Rick Braun, and more. In 2006, he reunited with Freeman and the Rippingtons for the group's celebratory 20th Anniversary album. He was also a member of Richard Smith's 2008 L.A. Chillharmonic project.
In 2009, Karukas reached number six on Billboard's Contemporary Jazz Albums chart with his GK album. Along with saxophonists Jessy J and Vincent Ingala, he also co-wrote, produced, and arranged two albums with pianist Omar Akram, including 2013's Echoes of Love, which won the Grammy Award for Best New Age Album. He reached number eight on the contemporary jazz chart with 2014's Soul Secrets. In 2021, Karukas delivered his first-ever solo piano album, Serenata, which featured his original compositions alongside his interpretations of works by Brazilian artists including Milton Nascimento, Clube da Esquina, and Dori Caymmi. ~ Matt Collar, Rovi