The double gold medallist fought off five rivals to be crowned the Conservative candidate for Colchester in Essex.
Mr Cracknell will stand to replace outgoing MP Will Quince, who is quitting politics to “put family first”.
The Olympian has long been tipped for a career in Westminster, having previously tried to be a candidate in Henley.
Mr Cracknell won gold in the 2000 and 2004 Olympics as a member of Great Britain’s coxless four crew.
In 2010, four years after retiring from rowing, the 51-year-old travelled to the US to film a series that would see him run, cycle and swim across the country.
During one of the cycling stints Mr Cracknell fractured his skull in a freak accident.
It’s only thanks to his bike helmet that the ex-Olympian is still alive.
After the accident, Mr Cracknell admitted he was quick to “get frustrated, lose my temper and train of thought”.
The former rower married TV presenter Beverly Turner in 2002.
They divorced in 2019, when Mr Cracknell took part in Strictly Come Dancing, and in 2021 he married financier Jordan Connell.
Paul Dundas, the Conservative group leader in Colchester, said: “James was the clear choice of members.
“I think he will be a fantastic candidate and a great MP for Colchester.
“He will win because he is a guy who doesn’t do losing.”