The CMA said Google's market dominance was unquestionable.
"We have found that Google maintains a strategic position in the search and search advertising sector – with more than 90% of searches in the UK taking place on its platform," CMA digital markets boss Will Hayter said.
"Having taken into account the feedback received following our proposed decision, we have today designated Google's search services with strategic market status."
The CMA previously unveiled what it called a "roadmap" of potential measures it could take if Google was found to have significant market status.
It said it could potentially force the tech giant to include "choice screens" which would let users see alternative search providers, as well as giving publishers more control over how their content was used.
It also included what it called "fair principles" for how websites are ranked in search results, and an "effective complaints process" for businesses unhappy about their listing.
The move has been well-received by consumer groups, with Which? policy boss Rocio Concha calling it "an important step".
"The CMA's careful evidence gathering makes a compelling argument," she said.
"Online search is evolving as GenAI tools become more widely used, but the CMA must still act to tackle the harmful dominance Google has now."
This is not the only regulatory action the tech giant is facing, as countries around the world consider whether it has become too dominant.
In the US on Monday, the Supreme Court decided not to intervene in a judge's order which required sweeping changes to be made to the Google Play Store.
But the tech firm won a battle in the same jurisdiction over long-running fears it may have had to sell Chrome or Android.
It was handed a €2.95bn (£2.5bn) fine by the EU in September, for allegedly abusing its power in the ad tech sector - the technology which determines which adverts should be placed online and where.