He's the third man to take up the role since the government was formed.
The Taoiseach's appointed Charlie McConalogue as the new Agriculture Minister.
The Donegal TD, who was previously Fianna Fáil's Agriculture Spokesperson, is the third person to hold the position since the government was formed at the end of June.
He succeeds Dara Calleary, who resigned after last month's Oireachtas golf society dinner, and Offaly's Barry Cowen, who was sacked following the controversy over a drink-driving ban four years ago.
Wexford TD James Browne replaces Deputy McConalogue as Minister of State at the Department of Justice.
Michéal Martin nominated the new Agriculture Minister in the Dáil this afternoon:
It is a privilege to be called to serve in Cabinet. I wish Charlie McConologue all the best in Agriculture, Food and Marine. He will be a great Minister in a great Department.— Barry Cowen (@CowenBarry) September 2, 2020