Una Chin-Riley started her career with Starfleet in the mid-23rd century, when she was assigned to the USS Martin Luther King Jr. as an Ensign. It was during Una’s time serving on this vessel that she encountered and rescued La’an Noonien-Singh from Gorn captivity. Inspired by Una’s actions, La’an would later join Starfleet herself. By the mid 2250’s, Una was serving aboard the USS Enterprise as helmsman and first officer to Captain Christopher Pike. Una would soon earn the moniker of “Number One”, a name she would diligently carry in service and representation of her ship and fellow crew.
By the end of the 2250’s, Number One had been fully promoted to the rank of Commander, and was assigned to command the crew of the USS Archer. The Archer’s mission was to make first contact with the inhabitants of Kiley 279 after the potential detection of a warp drive on the planet’s surface. However, when first contact with the inhabitants of the planet went awry, Number One was taken hostage along with other members of the Archer’s crew. After a successful rescue mission conducted by Captain Pike and his away team, Number One returned to her post as first officer of the USS Enterprise.