Minnesota Education Commissioner Mary Cathryn Ricker has resigned after two years on the job, saying she wishes to return to classroom teaching, Gov. Tim Walz announced Tuesday.

Ricker's last day will be March 19, according to her resignation letter. Deputy Education Commissioner Heather Mueller will take the helm of the state agency April 1.

"Watching the indefatigable work of Minnesota's educators, I feel the pull to spend my time and energy in classrooms working safely alongside them helping students," Ricker wrote in her letter. "As we well know, this pandemic is not impacting all our students and their families equally. … We all have a role in closing gaps and ending disparities and I am drawn to a role to provide more direct service and support to our students and educators this spring."

Before she became commissioner, Ricker was a longtime teacher who led two powerful teachers unions; she was once president of the St. Paul Federation of Teachers and executive vice president of the American Federation of Teachers.

Ricker said she will share details of her next role "in the coming months."

Mueller's career in education has spanned 24 years. She started as a high school social studies teacher at Mankato Area Public Schools in 1997, continuing to teach in the classroom for 11 years before eventually joining the state Department of Education, where she served as assistant commissioner and later deputy commissioner.

Mueller has played a leading role in the agency's response to the COVID-19 pandemic, including outlining plans for reopening schools at a recent news conference. As commissioner, Mueller will oversee nearly 330 public school districts, 164 charter schools and thousands of teachers and administrators.

"Minnesota's students and teachers have shown resiliency and perseverance this past year, and I look forward to partnering with our school communities to meet their diverse needs as we recover from this pandemic and continue building the best education system in the nation for each and every student in Minnesota," Mueller said in a statement.

Walz touted Mueller as an educator who is "deeply committed to the success of our students."

"There is no better person to lead our state at this critical moment," he said in a statement.