In the lengthy statement, she said she wanted time to focus on her family.
“I believe that being a parent is life’s greatest gift and greatest responsibility,” she said.
“I have thought deeply about this and I know that as a mother, I will feel profound regret if I don’t further focus on my young son’s safety, growth, and happiness – particularly at his tender age.”
Blakeman, a two-term Republican executive for Nassau County, in Long Island, New York, had announced his bid for governor earlier this month, setting up a primary clash with Stefanik.
A spokesman for New York Governor Kathy Hochul’s campaign on Friday said that Stefanik has “finally acknowledged” the reality that she would lose the race against her.
Ryan Radulovacki added that “Hochul’s message to him [Blakeman] or whichever lackey Trump picks to run against her is simple: Bring it on.”
President Trump had not taken a side ahead of the expected tough primary, telling reporters recently: “They’re both great people. We have a lot of great people with the Republican party.”
On Truth Social on Friday, he said Stefanik is “a tremendous talent” adding he is “with her all the way” regardless what she does.
Stefanik, 41, has represented New York’s 21st congressional district, which is north of Albany and includes the Adirondack Mountains, since 2014.
She has been a staunch ally of Trump, emerging as one of his most vocal supporters during his first impeachment in 2019.
For his second term, Trump initially nominated her for United Nations ambassador but withdrew her nomination due to considerations about the Republicans’ majority in the US House of Representatives.
The last Republican governor of New York, George Pataki, served until 2007.