When he was a young man, his family purchased a Terran slave named Elias Vaughn, who had been an officer in the Imperial Starfleet prior to the conquest of the Terran Republic, the successor state of the Terran Empire, by the Klingon-Cardassian Alliance in 2295. As Jaro was a member of the Bajoran dissident movement which sought the withdrawal of Bajor from the Alliance, he was treated humanely and was eventually given his freedom. However, the pretense that he was Jaro's slave was maintained in order to prevent the Alliance growing suspicious.
By 2377, he was married to Winn Adami and, along with her and Opaka Sulan, was a member of the leadership triad of the dissident enclave in Vekobet in the Kendra Province of Bajor. The enclave was passed off as a labour camp in which the vital metal uridium was processed by slaves. In reality, the slaves, who were composed of Terrans as well as Bolians and Tellarites, were agents of the dissident movement, as were their supposed Bajoran masters. Vekobet boasted rich veins of uridium, meaning that the enclave regularly exceeded the Alliance quotas. The excess uridium was transported to their allies elsewhere on Bajor. Jaro posed as the camp's physician and devoted much of his time to caring for Vaughn, who had then was a blind and extremely frail centenarian who was confined to a hospital bed. He was assisted in doing so by Vaughn's daughter Prynn Tenmei.
In January of that year, Vaughn's primary universe counterpart Commander Elias Vaughn and his superior officer Captain Kira Nerys made contact with the enclave and warned that the Iliana Ghemor of their universe was planning to discover the Bajoran wormhole and become the Emissary of the Prophets. Shortly afterwards, Klingon forces from the IKS Negh'Var launched an attack on Vekobet. Recognising that he would slow down Prynn and the other dissidents, Vaughn asked his counterpart to kill him. Commander Vaughn did so by shooting him with his phaser, which led to Prynn physically attacking him.
During their captivity on Terok Nor, which had recently been retaken by the Alliance, Jaro and Winn told Commander Vaughn that they understood why he had killed his counterpart and that they forgave him for doing so. However, Commander Vaughn doubted that Prynn would be as forgiving. With the assistance of the Jem'Hadar Taran'atar, Jaro, his wife and their fellow dissidents were freed while Terok Nor was recaptured by the Defiant with support from a fleet of the Talarian Republic vessels. Jaro and Winn subsequently returned to Bajor.
When Kira, Iliana Ghemor and the latter's mirror universe counterpart made contact with the Prophets, one of them took Jaro's form. After the Prophets chose the mirror Ghemor as their Emissary, this Prophet noted that she was not "the Sisko" but that she would do. (DS9 novel: The Soul Key)