Defendant broke the records set by Legend of the Blue Sea and Goblin early in the year when it breached 25 percent ratings in its second to the last week. It again repeated the feat when it reached closely 30 percent ratings in its final week.

Based on ratings released by AGB Nielsen Korea, Defendant's national ratings score for its 15^th episode reached 25.6 percent and ranked even higher in the Seoul National Capital Area. TNmS Media Korea, in its survey rated the 16^th episode slightly lower at 21.3 percent on the national rankings and 24.6 in the Seoul National Capital Area.

The ratings for the penultimate week seemed like the show was on track to hit an unprecedented 30 percent ratings. While it missed the 30 percent mark, Defendants ended strong with a national ratings 28.3 percent, reported Soompi.

Defendant, which topbills Ji Sung, started off strong in the ratings when it premiered on January 23 with 14.5 percent. It steadily increased in the following weeks as more people got hooked to the drama. By its seventh episode, it already averaged 20 percent in the ratings, which is already the peak of hit dramas "Legend of the Blue Sea" and "Goblin."

Defendant revolves around Park Jung Woo, a prosecutor who finds himself in the death row after he was accused of killing his family. Unfortunately, he is suffering from amnesia, rendering him incapable of defending himself in court. As the weeks unfolded, so did conspiracies and plots that further thickened the plot and made the drama even more gripping.

Like Defendant, Ji Sung's previous drama "Kill Me, Heal Me," was also widely praised by critics and even earned the actor coveted Korean Producers Award for Best Performance. However, it averaged around 10 percent and was nowhere near the average ratings of Defendant.