"I'm proud to announce that I've asked Tim Walz to be my candidate", she writes on Instagram.
"One of the things that stood out to me about Tim is how deep his conviction is to fight for middle-class families. It's personal", she continues to motivate her choice.
Minnesota Governor Tim Walz, 60 years old, was previously highly ranked in the US National Guard, is a former teacher and has long political experience from Congress. He has sailed up as a favorite among Harris in recent weeks.
According to CNN, Walz is also said to have been a favorite among Kamala Harris' campaign staff. Harris is reportedly impressed by Walz's carefree attitude and happy presence and is believed to be able to help win over Republican Donald Trump.
Attract voters in the Midwest
By choosing Walz, Harris hopes to strengthen her position in the upper Midwest – a critical region for presidential politics that often functions as a buffer for Democrats seeking the White House, according to AP.
Walz was initially an outspoken defender of Joe Biden after the president's catastrophic debate performance at the end of June, which led to demands for Biden to withdraw from the election campaign.
When Biden eventually dropped out, Walz gave his public support for Harris the very next day. Since then, Walz has emerged as a reliable and strong advocate for Harris.
The choice is criticized by Trump
Kamala Harris' choice receives early criticism from Donald Trump's camp.
"If Walz doesn't tell the truth to voters, we will: just like Kamala Harris, Tim Walz is a dangerous liberal extremist", says Karoline Leavitt, Trump's campaign press secretary, in a statement.
The duo is expected to appear together for the first time later on Tuesday in Philadelphia.
The duo is expected to accept the party delegates' nomination at the convention in Chicago on August 19-22.
In the presidential election on November 5, they will face off against Donald Trump and his vice presidential candidate JD Vance.
