Described as a "rogue", he was a confident person with a quick wit. He often charmed women who were attracted to his mischievous manner.
He was a close friend of Benzan and his family. Because of this, in 2365 Benzan asked him to transport a family jewel, the Jewel of Thesia, to a woman he had been seeing and intended to marry. He agreed, and went to Atlec to deliver it in his ship. Instead, his ship broke down, and accepted help from the USS Enterprise-D which happened to be close by. He boarded the Enterprise to observe repairs, however, unbeknownst to him, both Benzan's father and the woman's father, Debin, were after him, believing he had stolen the jewel and impregnated his daughter, respectively. Captain Jean-Luc Picard, aware that releasing Okona to either one of them could cause a war, beamed the parties aboard the Enterprise-D to discuss the matter. Okona declared he would hand himself over to Debin rather than be treated as a thief. Instead, Benzan decided to reveal the truth, exonerating him. (TNG: "The Outrageous Okona")
In the Myriad Universes story, "The Embrace of Cold Architects," in a universe where Picard is killed when the Enterprise destroys the invading Borg cube with its deflector dish weapon, Captain Riker recruited Thadiun Okona to take over hosting duties in Ten Forward after Guinan elects to leave the Enterprise.