In the movie, Ali G (played by Sacha Baron Cohen) is a boisterous and clueless young man living in the London neighborhood of Staines. He spends his days hanging out with his crew, getting into trouble, and trying to impress his crush, Julie (played by Kellie Bright).
Meanwhile, the Chancellor of the Exchequer (played by Charles Dance) is plotting to overthrow the Prime Minister (played by Michael Gambon) and take his place. He sees Ali G as a way to discredit the Prime Minister, by having him embarrass himself in public.
The Chancellor recruits Ali G to run for office as an MP, thinking that he will be easy to control and manipulate. Ali accepts the offer, but quickly finds himself out of his depth as he tries to navigate the complex world of politics.
However, instead of embarrassing himself, Ali's irreverent and comedic approach to campaigning strikes a chord with disillusioned young people across the country. He becomes a sensation, drawing huge crowds to his rallies and getting unprecedented media coverage.
As Ali's popularity skyrockets, the Prime Minister's team realizes that they need to embrace his message of youth empowerment and embrace his style of campaigning if they want to win the upcoming election.
In the end, Ali realizes that he has been used as a pawn in the Chancellor's scheme, but he still manages to save the day by exposing the Chancellor's corruption and helping the Prime Minister consolidate his power. The movie ends with Ali being embraced as a hero by a wildly cheering crowd, while Julie finally reciprocates his feelings for her.