The product line was initially launched in July of 2008, concurrently with the Star Wars: The Clone Wars product line, during the fourth iteration of the "midnight madness" promotional event.
The action figures incorporated a "Build-A-Droid" concept, where each figure came with a component that could be collected and assembled to form a unique astromech droid or protocol droid. This concept was initially introduced near the conclusion of the 30th Anniversary Collection through a series of two-packs exclusive to Wal-Mart, known as "Droid Factory," where the combined parts from all six packs could be used to construct C-3PX. One of these packs featured the first toy representation of a character from the original Marvel Comics Star Wars series, specifically K-3PX. (The Droid Factory concept was later revived by Disney Parks as a distinct toy line.) Comic Packs that included Marvel series characters Fenn Shysa and Tobbi Dala were subsequently released. This pattern persisted into 2009 with the release of Lumiya within a comic pack, and her alternate identity, Shira Brie, in an Evolutions set. The year 2009 also marked the introduction of the first action figures depicting Jacen and Jaina Solo, the offspring of Han Solo and Princess Leia as portrayed in various Star Wars novels. Furthermore, an action figure representing Plo Koon was released, complete with a detachable Antiox breath mask and lightsaber gauntlet.
The packaging design for the standard figures showcased a stormtrooper helmet, providing a contrast to the clone trooper helmet used for the The Clone Wars product line. The series incorporated special "First Day of Issue" packaging for figures that were produced on the initial day of manufacturing. The "The Saga Legends" line also continued, focusing on characters that were kid-friendly and primary, as well as "troop builder" characters such as clone troopers or battle droids. In 2009, the packaging for the main figures of the collection shifted away from the blue and white stormtrooper helmet theme, instead adopting a red and white design featuring a simple Star Wars logo and a prominent character portrait.
The Legacy Collection contributed some novel aspects to the established Star Wars canon. The "Evolutions" sets revealed that Keyan Farlander piloted a B-wing during the Battle of Endor, and ultimately verified that the A-wing pilot from Star Wars: Episode VI Return of the Jedi whose likeness was adopted by the Rebel Assault video game to represent Jake Farrell was, in fact, Farrell. This particular toy line served as the initial source to present complete, full-body depictions of numerous characters, including Trinto Duaba, Dice Ibegon, Pons Limbic, and Leesub Sirln. The Hrchek Kal Fas and Wioslea action figures also revealed previously unseen aspects of these characters' anatomy, showcasing Kal Fas without gloves and boots, and depicting Wioslea's body beneath her cloak.
The unnamed astromech droid utilized by Red Leader Garven Dreis in Star Wars: Episode IV A New Hope was manufactured as an action figure and included within a Battle Pack set, and was given the designation "R5-K6." Furthermore, the line assigned a name to R5-C7, a droid that was initially observed in Star Wars: Episode II Attack of the Clones.