Renard Sanderlin was born on the world of Rijeka, the son of quillar farmers, Albert and Nadine Sanderlin. Prior to entering military service, Sanderlin began dating a young woman named Rebecca Waldeck, a relationship that continued despite the long distance put between them. Despite his relatively humble origins, Sanderlin was accepted into the prestigious Nagelring Academy on Tharkad. In his third year at the academy, Sanderlin met fellow third-year cadet Victor Steiner-Davion, the Heir-designate to the united Federated Commonwealth. Sanderlin and Steiner-Davion became fast friends, with Sanderline helping Steiner-Davion through his cryophysics and astronavigation classes. Steiner-Davion respected that Sanderlin valued his friendship without interest in personal favor, while Sanderlin valued that Victor wanted no special treatment. The two were roommates for their final year at the Nagelring, and both graduated in the top five percent of their class. At Victor's recommendation to his cousin, Morgan Hasek-Davion, Sanderlin was assigned to the First Kathil Uhlans. Although Victor had brought Sanderlin to Hasek-Davion's attention, he was careful to note that Morgan would not have accepted him if Sanderlin's record didn't measure up.
On 19 May, 3049, Sanderlin and Steiner-Davion attended their graduation ceremony at the Nagelring. Sanderlin's parents attended, along with Rebecca Waldeck. There they met Victor's parents, Archon Melissa Steiner and First Prince Hanse Davion, who were honored to meet Sanderlin, whom Victor had told them about.
Though only a junior officer, Sanderlin reportedly participated in Kommandant Victor Steiner-Davion's planning sessions on Sudeten in 3050, sessions resulting in the Twycross operation. At some point, Sanderlin saw action against the Clans in an undocumented incident with the Uhlans. By his own admission, he did not perform well as a lance commander. After the fighting, Sanderlin was diagnosed with combat fatigue, spending some time back home on Rijeka during the Year of Peace. While back on Rijeka, Sanderlin finally married his sweetheart, Rebecca Waldeck. The two were expecting their first child in May 3052.
When Steiner-Davion began forming a new unit within the Tenth Lyran Guard, the Revenants, Sanderlin quickly volunteered to transfer. Meeting with his old friend on Port Moseby in February 3052, Victor told Sanderlin that he could not offer him a lance command, but that if Renny were willing to accept a demotion, he would be accepted. Sanderlin was with the Revenants during their operation on Teniente in May 3052. During the combat, he fought beside his old friend, warning him when a Nova Cat Vulcan attacked. Sanderlin recorded two kills in the fighting, although his own 'Mech was knocked out of action.
Sanderlin was still with the Tenth Lyran Guards during Operation Bulldog. Taking part in the "Dream Team" offensive on Schuyler, Leftenant Sanderlin was with Victor on the 13 August, 3059 when the pair was cutoff from the Guards in the Mitsuhama Ridge. Confronting an Omega Star from the Fourth Jaguar Regulars. Sanderlin took out a Grendel, then ran interference for the Prince, assisting his friend in downing a Man O' War, then finished off a Hankyu. With the enemy star destroyed, the two warriors realized that the rest of the Smoke Jaguars were in full retreat, pulling off planet. Sanderlin's 'Mech took serious damage in the fight, but he was otherwise unharmed.
- Sanderlin and Steiner Davion apparently feuded somewhat with another cadet at the Nagelring, Ciro Ramirez, an arrogant scion from House Ramirez.
- As a fourth-year student at the Nagelring, Sanderlin resided in the Kell Hall dormitories.
- Lethal Heritage, pp. 27,29, Sanderlin's relationship with Rebecca Waldeck
- Lethal Heritage, p. 28, Sanderlin and Steiner-Davion graduated in the top five percent at the Nagelring
- Lethal Heritage, p. 28, Sanderlin assists Victor Steiner-Davion in his classes
- Lethal Heritage, pp. 28-29, Victor Steiner-Davion recommends Sanderlin for the Uhlans
- Lethal Heritage, pp. 32-34, Sanderlin's parents attend his graduation
- Lost Destiny, p. 118, Sanderlin was part of the Twycross planning sessions
- Lost Destiny, p. 118, Sanderlin gets into trouble with the Uhlans
- Lost Destiny, p. 117, Sanderlin is diagnosed with combat fatigue
- Lost Destiny, p. 119, Sanderlin marries Rebecca Waldeck
- Lost Destiny, p. 119, Sanderlin joins the Tenth Lyran Guards
- Lost Destiny, pp. 257-263, the Revenants fight on Teniente
- Grave Covenant, pp. 296-302, Sanderlin fights beside Victor again on Schuyler
- The Dragon Roars, pp. 50-51, "Scenario 11: Breaking the Ridge", Sanderlin fights next to Victor on Schuyler
- Lethal Heritage, pp. 29-30, Sanderlin and Steiner-Davion deal with Ciro Ramirez
- Lethal Heritage, p. 29, Sanderlin celebrated in Kell Hall