The deal is worth $US110 billion ($A158 billion).
US District Court Judge Araceli Martínez-Olguín on Wednesday approved a September 21 settlement with a California-led group of 12 states that had sued to block one of the largest media mergers in history, saying it would create a media behemoth capable of driving up film and TV prices.
Under the settlement, the combined company must release at least 30 films a year in US theatres for five years and spend an extra $US300 million ($A432 million) a year on US production. Falling short of the film quota could force it to sell Miramax.
It must also negotiate basic cable deals separately for the two companies' channels and create a board of journalists to oversee CBS News and CNN.
Groups opposed to the merger objected strongly to the settlement, with some urging the court to reject it.
Martínez-Olguín called the deal a "reasonable factual and legal resolution," saying objectors' hopes for the decree "to reach farther – to achieve more – do not rise to the level of legal violations" warranting rejection.
A spokesperson for the California Department of Justice said the settlement "resolves our antitrust concerns..., protects competition and consumer choice, and centres the needs, concerns, and futures of California workers".
A Paramount spokesperson did not immediately respond to a request for comment on the order.
The companies also settled a Writers Guild of America antitrust lawsuit, agreeing to pay $US17.5 million ($A25.2 million) to the guild's health fund and maintain WGA staffing levels at CBS News for five years.
Separately, Paramount said Mattel CEO Ynon Kreiz will join on October 5 and become co-CEO when the deal closes alongside chairman and CEO David Ellison, running day-to-day operations and integration.
Kreiz, Mattel's CEO since 2018, turned the toymaker's brands into films, TV shows and games, delivering Barbie, Warner Bros' highest-grossing film ever.
The hire gives Ellison, whose background is on the creative side, a seasoned operator who steered Mattel through the pandemic and tariffs, as Paramount aims for more than $US6 billion ($A8.6 billion) in savings from the merger.
Before Mattel, he spent much of his career in TV and digital media, co-founding Fox Kids Europe and running "Big Brother" producer Endemol.
He later ran YouTube network Maker Studios, which he sold to Disney in 2014.
