Ronan was born into one of the leading Kree aristocratic families on Hala. After completing his education he was accepted into the ranks of the Accuser Corps, where he quickly rose through the ranks. Eventually he was promoted by the Supreme Intelligence to the rank of Supreme Public Accuser.
One of Ronan's missions was to punish the Fantastic Four when they defeated a Sentry left on Earth. But when he traveled to Earth and faced the four heroes, he was soon forced to use his own weapon on himself, giving himself the same sentence that he intended to mete out upon them. Unable to seek revenge due to the Supremor's orders, Ronan joined with Imperial Minister Zarek to depose the Supremor but was defeated by the Avengers.
Later Ronan made another attack against the Four when he attempted to gain possession of a Universal Power Core from Uatu The Watcher's house. With the aid of a mind-controlled Invisible Woman he was able to breach the dome but was only able to obtain the plans to one of them.
After a failed attempt to absorb Ego into himself, Ronan returned to his post as the Supreme Public Accuser and is helping the Supremor evolve those Kree who were able to avoid being turned into Ruul.