Ms McKenzie said the appointment was an "incredible honour and one of the proudest achievements in my life".
"Having grown up in regional Victoria, I have seen and experienced many of the substantial challenges and tests that rural and regional Australians have faced," she said.
"Australia's agriculture industry is one of the most important sectors to not just our economy, but also to our regional communities.
"It is worth $60 billion to our GDP and employs more than 300,000 Australians, the majority in small business.
"Successful regional communities mean a successful Australian economy and a better standard of living for all.
"We have seen in the past 18 months, the terrible toll that the drought and other natural disasters have had on our agricultural sector and I want to thank the Prime Minister for acting so quickly to help regional Australians tackle these adversities.
"I look forward to helping the agriculture sector grow to become a $100 billion industry and employing many more thousands of Australians."
Ms McKenzie said the futures of the fishery, forestry, food and fibre sectors were critical to ensuring Australia remained a competitive export nation, along with providing the essential food and other produce for the nation.
The Victorian Senator hit the ground running with some big issues to tackle including animals activism, the live export trade and reaching the goal of a $100 billion agricultural industry by 2030.
Ms McKenzie is expected to visit WA in the near future to engage with producer groups, tour a live export vessel and meet with her State counterpart, as well as The Nationals WA team.
She said being the first woman to take the role was an honour but gender was irrelevant to doing the job that's despite a positive reaction from young regional women across the country.
Ms McKenzie replaced her Nationals colleague David Littleproud, who kept the water and drought response portfolios.
The Nationals WA deputy leader Jacqui Boydell said Ms McKenzie's appointment was a "massive achievement" and having "done the hard yards, she really deserved it".
"She understands the industry, is energetic and dynamic and ag really needs someone like that," Ms Boydell said.
"It's breaking some glass ceilings.
"We are still talking about people being the first in 2019 it shows we still have a lot of work to do in the gender diversity space.
"She can only be a leader in that.
"There's a lot of women involved in ag so it is not surprising to have a female leader, but it is breaking new ground.
"It's a win-win.
"She is a fantastic role model being a mum, a teacher, professional and a leader.
"I hope it does encourage more women to play a role."
National Farmers' Federation president Fiona Simson said the appointment of the first female Federal Agriculture Minister was "momentous".
"The gravity of Senator Bridget McKenzie's appointment can't be ignored," Ms Simson said.
"We must acknowledge our first female Agriculture Minister and commit to each playing our role in ensuring the path laid by Senator McKenzie is well worn by many others after her."
Ms Boydell said there were some major challenges in agriculture, "particularly in WA and we want to capitalise on ag investments and opportunities but we need the right minister".
"Ms McKenzie has been a great friend to WA, she has always been a visitor to WA and understands WA," she said.
"She's not scared to get on a plane and get over here.
"We have a good working relationship with her and only see it developing further."
Ms Boydell said the reduced portfolio would be good for the Minister because it will ensure she is able to focus on the industry without being distracted by other complex issues.
"If you look at her past, she's never shied away from serious challenges and we have major challenges with animal activism and live exports that we've never seen before," she said.
"That tricky public perception and animal welfare over activism she'll be able to plot a pathway through all that."
Ms McKenzie was first elected as a Victorian senator in 2010 and re-elected in 2016 and has since served in a number of capacities, including as Minister for Rural Health, Sport, Regional Communications, Regional Services, Local Government and Decentralisation.
She was also The Nationals Party Whip in the Senate from 2013-2014.
Before entering politics Ms McKenzie taught secondary school mathematics and physical education and then became a lecturer in the education faculty at Monash University, Gippsland, Victoria.
With Anthony Albanese replacing Bill Shorten as Labor Party leader and reshuffling his front bench he has made some changes to portfolios, however Joel Fitzgibbon has been reappointed as spokesperson for agriculture and resources.