Kramer, 27, recently signed a record deal with Warner Music Nashville. She says that her first song, which appears on her website, is "about never giving up on those that you love."
She said in August 2010 that she and fellow actor Johnathon Schaech had broken up. The two had wed a month earlier.
"I Won't Give Up" can be purchased at Apple's iTunes music store in both its original and acoustic form.
"I wrote this song because I know what it feels like to be on both sides and I know how it feels to need someone when you're going through a hard time," Kramer says in a video posted on her website.
"One Tree Hill" is currently on its eighth season. The CW network, owned by CBS Corporation and Warner Bros., has not yet announced plans to air a ninth.