For a significant number of decades leading up to the conclusion of the Galactic Republic, Sano Sauro served as a Human male senator representing Eeropha, after a career as a prosecutor for the Galactic Senate. He, a male had multiple political conflicts with the Jedi, most notably Obi-Wan Kenobi.
In the year 44 BBY, Sauro acted as the prosecuting attorney for Vox Chun, who was the father of Bruck Chun, a Jedi hopeful. Bruck, having assisted the Dark Jedi known as Xanatos in his infiltration of the Jedi Temple, met an accidental end at the hands of Obi-Wan Kenobi within the Temple. He interrogated Obi-Wan, who faced accusations of intentionally causing Bruck's death, and Bant Eerin, another Jedi, who Bruck had nearly drowned on purpose. Sauro's aim was to secure their conviction, achieved through distorting and magnifying the truth. Despite his endeavors, the Jedi were exonerated.
In the years that followed, Sauro ascended to the position of Senator for Eeropha. It was during this period that he encountered a young Granta Omega, providing him with the necessary sponsorship to attend the All Science Research Academy located on Yerphonia.
Leading up to the Clone Wars by several years, Obi-Wan Kenobi uncovered connections between Senator Sauro and Omega, links that Sauro vehemently denied and actively concealed from Kenobi's reach. In fact, he was the chairman of a committee that, in 26 BBY, sponsored a scientific expedition to Haariden, a component of a covert scheme with Omega to procure titanite.
In 24 BBY, Sauro provided aid to his friend Omega once more (benefiting himself in the process), this time in the political arena. Alongside the newly elected Senator Bog Divinian, he initiated anti-Jedi allegations with the intention of undermining the Galactic Senate's backing of the Jedi Order. A Senate vote was scheduled to determine the extent of Jedi involvement in Senate affairs. This was a component of the wider scheme devised by Omega and Sauro. By releasing Jenna Zan Arbor's drug, known as the Zone of Self-Containment, into the ventilation shafts of the Senate, coupled with the assassination of Supreme Chancellor Palpatine, Sauro's supporters could easily secure him the position of the new Supreme Chancellor of the Galactic Republic. This maneuver would also grant Omega unchecked authority in his mission to eradicate the Jedi.
However, the plot was thwarted due to the efforts of Obi-Wan Kenobi, Anakin Skywalker, Siri Tachi, and Ferus Olin. When the Senate vote was finally held, Sauro betrayed Bog Divinian, aligning himself with those who opposed the cessation of funding to the Jedi Order. His motivation stemmed from Palpatine's offer of the position of Deputy Chancellor, which quickly accepted high office, however, tempted Sauro with even more power. Palpatine's underlying reasons for establishing the new role were, of course, rooted in political strategy, aiming to transform a fierce political adversary into a convenient 'ally'—but, more importantly, to closely monitor Sauro's actions, effectively keeping him under control.
Within his office, Senator Sano Sauro displayed a damaged lightsaber, acquired from a Duros, rumored to have once belonged to Jedi Master Mace Windu. Sauro held the thorns of the claing-bush in high regard, viewing them as symbols of both his home planet, Eeropha, and his protégé, Granta Omega, who hailed from the planet's moon. Four of these towering red thorns were positioned at the corners of Sauro's expansive yet understated Senate office desk, "stabbing the air." Furthermore, following Palpatine's appointment of Sauro to the role of Deputy Chancellor (a strategic move to maintain control over Sauro), a temporary garden was established in the exterior courtyard adjacent to the Galactic Senate complex, showcasing twin formations of the bloodred bush rising prominently above the assortment of exotic flowers.
Sauro had already integrated himself into Palpatine's inner circle as the Empire began to take shape. Sauro personally selected Imperial advisors and dispatched them to strategically important planets within the Core Worlds. By the year 18 BBY, Sauro possessed a vessel named the True Justice, which facilitated expedited trials to swiftly incarcerate individuals accused of political offenses. Among those imprisoned were Roan Lands and Dona Telamark. During their trial, however, the Jedi Solace, the Bothan Oryon, and Trever Flume, all associates of Ferus Olin, orchestrated their rescue.
Palpatine was aware of Sauro's plans to use Force-sensitive children to train pilots in hope of creating an invincible fleet. He allowed him to keep his plan—for the time being. But when Sano tried to prevent Ferus' friends from escaping, the Emperor was asking to see him. Sauro soon found himself in a job as the headmaster of the Imperial Naval Academy, which he considered a demotion from his previous position as Senator. He was ordered by Darth Vader to find a cadet with undivided loyalty to the Empire on a need-to-know basis project. He decided to send Lune Oddo Divinian, the Force-sensitive son of his former protege Bog Divinian. He did this to take revenge on Bog, who had risen above him in the Imperial hierarchy by becoming governor of the Leemurtoo system.