Goodwill is MP for Scarborough and Whitby and backed remain in the Brexit vote. Eustice is a keen leaver and has a horticultural background.
Defra secretary of state Michael Gove said: "Delighted to welcome Robert Goodwill to the Defra team. Robert’s hands on knowledge of farming at the sharp end, experience in European politics, great ministerial record and shrewd judgment are an asset to Government."
Goodwill, who became an MP in 2005, served as a whip and transport minister under David Cameron and was promoted to immigration minister, and then children's minister, by Theresa May before leaving the Government in 2018.
Goodwill has experience of horticultural issues having given evidence on overseas worker grower employment challenges during a EFRA committee inquiry in 2017, when he sat alongside Eustice answering EFRA committee members' questions.
Reaction came from organisations including the Crop Protection Association. Chief executive Sarah Mukherjee said: "I’d like to congratulate Mr Goodwill on his appointment at this crucially important time. I’d also like to place on record our gratitude for the work of his predecessor George Eustice. With his knowledge and farming background, Mr Eustice was a great advocate for sustainable, productive agriculture.
"I look forward to working with the new minister to help realise the opportunities presented by Brexit and ensure we have a regulatory system that is science-led and continues to support UK farmers in ensuring a healthy, safe and affordable food supply."
NFU president Minette Batters said: "I would like to congratulate Robert Goodwill on his appointment as the new Agriculture Minister and I am looking forward to working with him at such a critical time for Britain’s food and farming industry.
"I will be seeking a meeting with Mr Goodwill as a matter of priority to discuss the pressing issues currently facing farmers and growers, in particular the impact ongoing Brexit uncertainty is having on farm businesses and the need for Parliament to reach a deal with the EU, avoiding the devastating impacts of a no-deal Brexit.
"This is a pivotal time for British farming. The Agriculture Bill currently going through Parliament presents an opportunity to shape agricultural policy for generations to come. I will be stressing to the Minister the importance of having food production at the heart of this new policy, alongside measures to protect and enhance our cherished countryside.
"British farmers and growers are ambitious, innovative and up for the challenge of the years ahead. We know that the public take great pride in British food and farming and that is something we have an opportunity to enhance as we move forward.
"I look forward to meeting with the Minister at the earliest opportunity."
Country Landowners Association president Tim Breitmeyer said: "We would like to welcome Robert Goodwill to the role which comes at a critical time for farming.
"As a farmer himself he will be all too aware of the major issues and uncertainties landowners and farmers are currently facing across their businesses, and will have an innate understanding of the vital role they play for society as producers of food and stewards of the countryside. This can only be a positive for our members and the wider farming community.
"We know from previous ministerial roles that Robert is willing to listen and engage on the issues that matter and we are looking forward to him continuing the good work of his predecessor and working together to deliver a bright future for the rural economy