Her first season on DWTS (Season 3), she was partnered with TV personality Mario Lopez and finished in second place. After the show, the couple began dating. The relationship lasted from Fall 2006 to June 2008. Then in Summer 2008, Karina began dating fellow DTWS cast member Maksim Chmerksovsky. Six months later they announced their engagement. This lasted a mere nine months. Shortly after, Smirnoff began dating MLB pitcher Brad Penny. The couple became engaged on October 4, 2010.

Smirnoff returned to the show for Season 4 where she was paired with country singer Billy Ray Cyrus. Her partner for Season 5 was word champion boxer Floyd Mayweather. Some of her other partners on the series were singer Mario, chef Rocco DiSpirito, Apple co-founder Steve Wozniak, singer Aaron Carter, and Mike “The Situation” Sorrentino from MTV’s reality TV Show Jersey Shore. Her partner on Season 12 of the show is the original Karate Kid, Ralph Macchio.

In May 2011, Karina is set to be featured in a nude pictorial of Playboy magazine. This stint will not be her first public nude shots. Karina posed nude in a PETA advertising campaign with the tagline “I’d rather dance naked than wear fur.”