In Kale's usage, she becomes slightly taller with noticeable musculature increases in mass and definition, but not nearly as much as the Legendary Super Saiyan. Her hair taking on a dull yellow tint compared to usual Super Saiyans in its first appearance. However, the aura retains the untinted golden hue of a typical Super Saiyan transformation.
This form is a Super Saiyan form with perfect energy control. It is seemingly identical to and is a variation of the first Super Saiyan form, though is of a different evolution. In addition, in this form Broly is powerful enough to defeat both Goten and Trunks as Super Saiyans at the same time and is able to outmatch base Gohan, despite Gohan having powered up considerably since his previous encounter with Broly, though base Gohan is able to hold his own. Upon seeing Gohan turn Super Saiyan 2, Broly responded by taking on his Legendary Super Saiyan form. When Kale used the form she possessed enough strength to allow Kale to partake in the battle between Caulifla and Goku - who were both in the Super Saiyan 2 form, though it is weaker than the Legendary Super Saiyan form.
The form also is shown to be exceptionally fast, being able to move as if teleporting, which is especially evident by how Broly managed to get the drop on Goten and Trunks shortly after using Planet Geyser. However, the form has its limitations: using any particularly devastating attacks, such as Planet Geyser, carries the risk of harming the user unless they are protected beforehand by an energy shield.
A user of this form cannot maintain the form while they are either in a coma or otherwise asleep unlike the Super Saiyan Full Power state, which is especially evident in Paragus's flashback to his outfitting the crown onto Broly, and later when Broly fell into a coma seven years prior. It is also noted that the legendary Saiyan is born strong enough to become a Super Saiyan. Aside from the standard gold hair, it also has various different hair colors depending on the lighting, including Auburn as well as pink/purple and lime green.
Dragon Ball Z movies
Broly utilizes this form in flashbacks of Dragon Ball Z: Broly - The Legendary Super Saiyan, when becoming enraged at the appearance and mention of Kakarot he proceeds to transform from A-type Super Saiyan into C-type Super Saiyan (with green hair) - back to A-type Super Saiyan - and then into Legendary Super Saiyan.
Upon arriving on Earth in Dragon Ball Z: Broly - Second Coming, Broly transforms into this form, he utilizes it in his battles with Videl, Goten, Trunks, and Gohan until Gohan becomes a Super Saiyan 2, and thus Broly responds by becoming a Legendary Super Saiyan.
Dragon Ball Super
Kale gained this form when rather than feeling self-loathing she felt a greater desire to become better due to Caulifla's belief in her even in a dire situation, granting her control over her formerly Berserk form and also gaining this transformation. Kale utilized this form in battle with Kahseral's team of Pride Troopers, attaining it to break out of Cocotte's Cocotte Zone. She then uses it alongside Caulifla to clash with the Pride Troopers, before powering up into Legendary Super Saiyan. She later uses this form again in order to fight Goku in his Super Saiyan 2 form alongside Caulifla.