War Machine was found guilty though of coercion, dissuading a witness, battery by strangulation, kidnapping. and multiple counts of sexual assault.
The fighter's attorney Jay Leiderman conceded that his client was guilty of beating Mack during their relationship, but said that he was not guilty of attempted murder and sexual assault charges.
Koppenhaver, 35, carried out a brutal assault against Mack and Thomas in August 2014 which left Mack suffering from numerous injuries included a punctured lung and several broken bones.
The jury comprised of six men and six women heard eight days of testimony before deciding Koppenhaver's fate.
Jurors deadlocked Monday on two attempted-murder charges against Jonathan Paul Koppenhaver, but convicted him of 29 counts.
The 35-year old former fighter will now await sentencing on June 5 in Las Vegas. "What that says to domestic violence victims is that even if you don't report it right away, a jury can still believe you".
Thomas, a digital media company owner, testified that he dated Mack for two months before Koppenhaver arrived at her home unexpectedly, flipped on the bedroom lights and set upon him on the bed with rapid-fire punches and choking. She also had a ruptured liver that prevented doctors from initially operating on her for fear of putting her under anesthesia.
Koppenhaver was arrested a week later in the Los Angeles suburb of Simi Valley.
Koppenhaver went by his birth name during the two-week trial but had legally changed it to War Machine during his 19-fight MMA career.