In 3951 BBY, the captain, a Human, commanded the Harbinger.
The Harbinger was one of the few ships that remained to patrol Republic space after the Jedi Civil War. In 3951 BBY, while heading to Onderon to address the disturbances there, the ship received orders from Admiral Carth Onasi to change course for the Outer Rim. Despite the captain's reservations, the mission was deemed top priority by Admiral Onasi, and the Harbinger soon welcomed a passenger: Meetra Surik, who had recently returned from beyond Republic territories. With Surik aboard, the Harbinger set a course for Telos IV, with the intention of arriving within ten days to assist with the recovery efforts.
However, an HK-50 assassin droid disguised as a protocol droid, one of many scattered throughout the Republic fleet, had its own agenda. The captain tasked HK-50 with monitoring Surik, and the droid complied, albeit for its own reasons.

While en route to Telos, the Harbinger detected a distress signal from a freighter under assault by Sith forces. Unable to identify the vessel using its own databases, the Captain of the Harbinger relayed the signal to the Republic and requested authorization to investigate. Admiral Onasi recognized the freighter as the Ebon Hawk, a ship he had once traveled on, and granted the Harbinger's captain permission to alter course. The Harbinger was instructed to investigate the Sith presence and gather any available information on the Ebon Hawk before resuming its original course to Telos.
Upon arrival, the Harbinger discovered the Ebon Hawk alongside a Sith warship. Connecting an umbilical to the Sith vessel, they deployed three strike teams to conduct an investigation. The initial search yielded no results. Unbeknownst to the strike teams, Sith Assassins with stealth capabilities were aboard, allowing them to infiltrate the Harbinger undetected. A subsequent search revealed another passenger on the Sith ship—an apparently lifeless body covered in fractures and scars. The Harbinger's medical personnel were unable to determine if the individual was alive or dead, and subsequently placed them in a kolto tank.
The initial sweep of the freighter revealed only a T3-series utility droid and several deceased individuals. Finding nothing else of note, the Harbinger used a tractor beam to bring the Ebon Hawk aboard. It, too, carried an unexpected passenger—Kreia. Meanwhile, the Sith had been active. Crew members began missing shifts, some were unreachable via comms, and others felt as though they were being watched. The medical officer prepared to conduct autopsies on the corpses recovered from the Hawk.
The already-vulnerable Harbinger suffered another setback. HK-50, aiming to capture Surik for the crime lord G0-T0, orchestrated a cascade failure in the ship's communications, weapons, and engine systems. As a result, the Harbinger became crippled and drifted aimlessly through space. Surik, having received an excessive dose of sedatives during a medical examination, was hidden by HK-50 in the ship's cargo compartment, where he intended for her to remain until his reinforcements arrived. However, Kreia boarded the Harbinger in search of Surik. She located her in the cargo hold and brought her aboard the Ebon Hawk. HK-50, revising his plans, joined them.

The seemingly deceased passenger proved to be very much alive—it was in fact a Sith Lord, Darth Sion, who emerged from his kolto tank and declared his intention to capture Surik. Alarmed, the bridge sent a security team to the medbay, but they were swiftly eliminated. Sion began searching for more of the Harbinger's crew, and his Assassins began to decloak and join him. The Sith quickly gained control of the ship, and as the Ebon Hawk disengaged from the Harbinger and the capital ship's systems began to fail, the Harbinger fired upon the freighter, striking it as it jumped to hyperspace.
The captain, along with his officers and crew, perished when Darth Sion's Sith forces seized control of the vessel.
After the Harbinger docked with the Peragus Mining Facility, Surik was able to piece together the events that had transpired by reviewing logs kept by the Captain, as well as other officers.