Jayhawk functioned as a captain of pirates, in command of the freighter called the Martinette. To gain profit, he would falsely claim to be a privateer working for the Alliance to Restore the Republic.
The captain of the Martinette, Jayhawk, was a heartless pirate. The Martinette was a YT-1300 light freighter that had been modified and had a crew of eight, Jayhawk included. Mirthen, a Quarren pirate, was promoted to second-in-command by Jayhawk.
When attacking enemy vessels, Jayhawk frequently pretended to be a privateer holding a letter of marque and reprisal issued by the Alliance to Restore the Republic, otherwise known as the Rebel Alliance, in the hopes of intimidating them. However, the Alliance had no knowledge of Jayhawk. He successfully plundered several light freighters while posing as this false persona.
Around 1 ABY, Jayhawk journeyed to Abonshee and encountered Trisstan, the Godking of the Anointed People who were native to the planet. Jayhawk once again acted as a member of the Alliance on a diplomatic mission. However, after gaining Trisstan's confidence, Jayhawk absconded with a portion of his wealth and fled the world.
Shortly thereafter, Jayhawk and the Martinette launched an assault on a pleasure yacht named the Long Shot. At that time, Jayhawk was unaware that the Long Shot was actually owned by the Alliance.
Jayhawk was a cruel individual who murdered without any feelings of guilt. He was too practical to commit murder without a purpose, and he did not participate in the slave trade. Therefore, whenever he captured a crew or received surrenders, Jayhawk would abandon those individuals in locations where they posed no immediate danger, such as a planet without technology or an escape pod.
Jayhawk elevated Mirthen, a pirate with a drug addiction, to the position of second-in-command. This decision was not based on Mirthen's abilities but rather on the fact that Mirthen lacked ambition and would not plot against him.
Jayhawk was a slender man who preferred to wear black pants, white shirts, and red vests. He sported a very thin mustache. He typically carried a blaster pistol and a saber, and he was proficient in their use.