Not much is known about Oswald other then that he is a Staff Sergeant and a member of the 40th Infantry Divison from the National Guard. On August 11, 2011, he and his fellow troops were called to Los Angeles to defend the city from invading aliens. He and his group went into the city and engaged the aliens. After fighting the aliens, Oswald and any surviving members fell back hoping to reach the FOB (Forward Operating Base) at Santa Monica airport. On the way there, he and his group ran into Technical Elena Santos and she joined them. After some time, they met up with SSgt Michael Nantz, 2nd Lt William Martinez , and their marines. According to Oswald, the rest of his unit is either dead or missing. Instead of heading for the FOB, he and the remaining infantry members decided to help the marines get to the police station.
When they arrived, he and Dever assisted Nantz in securing and searching the station for survivors and aliens. After securing the station, Oswald and everybody else witnessed the arrival of the alien Wedge Ships and had to fall back to the station.
After some time, he and the others boarded a bus heading for the freeway. Once on the freeway, the bus witnesses a battle between soem Marines and an Abrams tank fighting the aliens. The group got off the bus to engage the aliens as well. The tank and its marine crew get defeated leaving Martinez and his marines alone to fight. Oswald participates in the battle and after the aliens get pinned down by them, he and Corporal Jason Lockett move up to secure a Humvee for use. Oswald covered Lockett until he managed to fire the Humvee's turret. After Lockett killed several alien forces, the aliens deployed a Walking Gun to deal with them. Oswald saw the weapon and began to retreat when it fired its missles at the car he was using for cover. The missles didn't kill Oswald but the explosion knocked Oswald to the ground, and the car flipped over and landed on Oswald, killing him.