The name Sakka bore in a previous birth when he was born as a man in Macalagāma in Magadha.
The usual form of the name is a derivative - e.g., J.vi.212; he is often called Maghavā Sujampati - e.g., J.iii.146; iv.403; v.137, 139; vi.102, 481, 573; or Maghavā Sakko - e.g., J.v.141; see also Mtu.i.165, 167 (sahasranetro Maghavān va sobhase) and Mtu.iii.366 (Sakro āha: Maghavān ti me āhu syaloke).
His story is given in the Kulāvaka Jātaka. For a slightly different version see DhA.i.264ff. Because of his birth as Magha, Sakka came to be known as Maghavā. Maghavā was, perhaps, not the personal name of any particular Sakka, but a title of all Sakkas, because the Sakka who was the real Magha is identified with the Bodhisatta (J.i.207), while the Buddha says (S.i.231; DhA.i.264) that the Sakka, who visited him, and whose conversation is recorded in the Sakkapañha Sutta, was also known as Maghavā. The title probably originated from the time when Magha became Sakka.
The Samyutta Commentary (SA.i.267; this is supported by the story as given in DA.iii.710 ff. and DhA.i.264ff., where no mention is made of the Bodhisatta), however, says that Magha was not the Bodhistatta, but that his life was like that of a Bodhisatta (Bodhisattacariyā viyassa cariyā ahosi); in which case the name Maghavā belongs only to the present Sakka.
Magha took upon himself seven vows (vatapadāni), which brought him birth as Sakka:
For this and other titles of Sakka, see Sakka.