Vito Corleone (Marlon Brando)’s Timeline and Summary

Vito grants favors to guests at his daughter's wedding (like Bonasera and Johnny Fontane), though he wants loyalty in return.
After he turns down Sollozzo's drug deal, hit men from the Tattaglia family try to kill him (they wanted to use political connections the Don was denying them).
Michael protects Vito from another assassination attempt while he recovers.
While Michael flees the country after polishing off two of his father's would-be murderers, Sonny assumes temporary control of the family. Vito Corleone is sidelined for a while.
But after Sonny is murdered, Vito starts making decisions again. He finds that he's been forced to make a truce with his enemies and go along with their drug-dealing schemes.
When Michael returns, Vito expresses his regret that Michael won't be able to have a legitimate career, now. But he tries to help him, giving him advice on how to spot the traitor (Tessio) within their ranks.
He dies from a heart attack while chasing his grandson around in his tomato garden.