Sandra Peterson, a tough labor union leader and a tender hockey grandmother, died early Saturday after a four-year fight against ovarian cancer. She was 79.

Peterson led the Minnesota Federation of Teachers (MFT) for more than a decade, then helped engineer a 1998 merger with the rival Minnesota Education Association to form Education Minnesota. She served as co-president and vice president of the merged union, then won a seat in the state House in 2004 as a DFLer representing New Hope.

Peterson served four terms before stepping down in 2012 after her cancer was discovered.

On Saturday, accolades poured in for Peterson’s long career in public service.

“She cared deeply about better educational opportunity for all children,” Gov. Mark Dayton said. Lt. Gov. Tina Smith said Peterson’s absence will be felt by many.

“Her efforts, over decades in public life, will have a lasting, positive impact on our state for many years to come,” Smith said. “We mourn her loss today, and celebrate her many accomplishments on behalf of Minnesota children, families and teachers.”

“Sandra was the kind of leader we all hope to be — kind, approachable, smart and firm when necessary,” said Denise Specht, president of Education Minnesota. “She was a courageous, visionary leader. She will be missed by those who knew her and remembered for her accomplishments as an educator and a union leader.”

Peterson grew up on a family farm in Benson, Minn., and graduated from Macalester College. She taught kindergarten and special education in the Robbinsdale schools for 17 years before her election as MFT president in 1987.

As a statewide advocate for teachers and students, Peterson fought hard and made a few powerful enemies. After she and her Education Minnesota co-president, Judy Schaubach, met with then-Gov. Jesse Ventura to argue for increased school funding, Ventura said he’d “never seen two more arrogant people” and accused the pair of acting like “the 800-pound gorilla.”

Peterson battled school voucher proposals and teacher cutbacks, and she pushed for smaller classes. She refused to equate effective education with an efficiently run business.

Always energetic, “she ran until the end,” said her son, Stephen Peterson. “Two weeks ago, she knew that she was having some [health] issues, but she went to a board meeting for the Children’s Museum, and she was going full speed.”

Peterson checked into the hospital and took a rapid turn for the worse. She spent her last week in hospice care, surrounded by family, friends and colleagues from her education and legislative days.

“She was dedicated to her family, especially her seven grandchildren,” Stephen Peterson said. “She was constantly doting on them, including driving my daughter nonstop to school and hockey. She was always there.”

Peterson is survived by three other sons, Eric Peterson, Mark Telen and Paul Telen, and four siblings. She was preceded in death by her husband, Richard Peterson, and her life partner, Alfred (Bud) Telen. Funeral arrangements are pending.