PHOENIX — A former president of the Arizona Board of Education who resigned his post last year amid an ongoing battle with state schools chief Diane Douglas has died.

Greg Miller died Tuesday of natural causes after battling coronary artery disease for years, said his daughter, Wendy Miller. He was 69.

Miller and his wife Pam founded the Challenge Charter School in Glendale in 1996 and he served on the Board of Education from 2010 until he resigned in August 2016. The board creates statewide school policies.

Wendy Miller said her father was most proud of his work as an educator. She said she’s received hundreds of calls from former students who said he had been like a second father to them.

Before opening his school, Miller volunteered as part of the group involved in discussions that led to the passage of the Arizona law authorizing charter schools in 1994, according to the Arizona Charter Schools Association. There are now more than 550 of the public schools across Arizona educating more than 180,000 children.

Miller’s time as Board of Education president is what made him a familiar name across the state as he and Superintendent of Public Instruction Diane Douglas faced off more than a year. When Douglas came into office in early 2015, she fired the board’s executive staff, a move that Gov. Doug Ducey blocked. More than a year of additional battles between the board and Douglas followed.

He resigned from the board in August 2016 after being pressured by Ducey, and said he hoped stepping down would end a political sideshow that had overshadowed the board’s work.

“It has never been personal for me,” Miller said at the time. “It has always been about defending the integrity of the state board and putting kids first, as I have done throughout 40 years of educational volunteerism.”

Miller was born in Long Beach, California, and had a 25 year career in civil engineering and land use planning before becoming an educator. He also served in the Utah National Guard.

Two years after Miller and his wife started their school, he designed the new campus that now houses more than 500 children in grades K-6. Wendy Miller is now CEO and principal, although her father was still board president and extremely active with the school.

“His legacy exists in the alumni, the thousands of people impacted,” she said.

In additional to Wendy Miller and his wife, Pam, Miller is survived by daughter Kelly Dawn Zollinger and three grandchildren.

Services are set for 3 p.m. on November 4 at Hansen Desert Hills Mortuary in Scottsdale.