The Biden administration is preparing to announce several ambassadorial appointments, including Ambassador to Ireland.
Ms Cronin was an early supporter of US president Joe Biden when he announced his run for the office, and helped fundraise for the former vice-president in the early days of the campaign.
A lawyer by training, she is a senior Democratic lawmaker in the Massachusetts state house and was the first female majority leader of the state legislature in Massachusetts history.
She represents the Easton district, south of Boston, and is married to Ray Cronin. The couple have two children.
The Trump supporter was appointed in June 2019, more than two years after Mr Trump’s election victory.
While Mr Biden has faced some criticism for leaving the most senior diplomatic posts vacant in capital cities across the world since his inauguration, he has announced a number of appointments in the last week.
Like all ambassadorial appointments, Ms Cronin must be approved by the Senate foreign relations committee before taking up her post in Dublin.
Ms Cronin campaigned heavily for Mr Biden in 2020, and formally announced the state’s delegate votes during the Democratic National Convention last year.
It is understood that there was intense competition for the position, with several people informally putting themselves forward for consideration.
Despite the nomination of an Irish ambassador, no decision has yet been made on the appointment of a Special Envoy to Northern Ireland, a position that was last held by former Trump chief-of-staff Mick Mulvaney.
It is understood that the governments in Dublin and London would welcome the appointment of an envoy specifically dedicated to Northern Ireland given the current political unrest in the North.