Tom Boasberg, who today announced his plans to step down as Denver’s schools superintendent, leaves behind nearly a decade of high-profile debates and decisions that reshaped the city’s public school system and made plenty of local and national headlines.

For years, Boasberg’s tenure featured sharp political divides among the city’s school board. His school improvement efforts, notably in the city’s Far Northeast neighborhood, garnered mixed results for students. And his embrace of nontraditional school management, the so-called “portfolio model,” has earned him national praise.

Here’s a chronological look back at a dozen stories that defined his nearly decade of leading Denver Public Schools.

Denver Public Schools “therapy” forges progress

In 2009, at a daylong meeting attended by Denver school board members, Boasberg, and a therapist, the superintendent and the board appeared to forge closer ties after a divisive school board election. The session at the tony Broadmoor Hotel included coaching board members and Boasberg through some difficult conversations about their respective roles – and Boasberg’s job security.

More shared campuses, still controversial

One of the first waves of school reform policies the district embraced was locating multiple schools on one campus. While Boasberg didn’t start the district’s practice of placing charter and district-run schools on shared sites, his administration did continue it — much to the dismay of some schools’ staff and community members.

Boasberg’s school improvement efforts in Far Northeast Denver take off

One of the superintendent’s earliest — and most ambitious — school turnaround strategies was to overhaul schools in the city’s Far Northeast neighborhood. The neighborhood, which serves a majority of black and Latino students, had the highest concentration of the city’s lowest-performing schools.

Boasberg: Manual’s shortcomings are my responsibility

No school in Denver has been subject to more improvement efforts — by multiple superintendents — than storied Manual High School. After some minor improvements, the school took a turn for the worse and by 2014 was once again the city’s lowest-performing school. After dismissing the school’s principal, Boasberg took ownership of the school’s downfall.

Denver Public Schools ‘ahead of the curve’ with proposed facilities policy

After years of opening and closing numerous schools, DPS began to formalize the process. One of its first stabs at systematizing its “portfolio model” was a facilities policy. The policy, which applies to both charter and district schools, would tie placement decisions to schools’ academic performance, student enrollment patterns, and other district priorities.

Why Denver Superintendent Tom Boasberg landed an unprecedented six-month break

In January of 2016, Boasberg took off for six months with his family for a trip to Latin America. The uncommon stability of Denver Public Schools made his respite possible, observers said.

Denver Superintendent Tom Boasberg’s vision for giving more power to schools, annotated

Denver Public Schools has long strived to be more decentralized and less top-down. More than a year after the school board granted school leaders more autonomy, Boasberg penned a document detailing how he envisions the district should function under that philosophy. Here we explain and provide context for Boasberg’s memo.

Efforts to better integrate Denver middle schools proving tough, analysis finds

One way Boasberg and Denver Public Schools attempted to fight school segregation was the creation of “enrollment zones.” The idea was that extending boundaries and asking students to choose from several schools within them would increase integration in a gentrifying city where many neighborhoods are segregated. But there was little evidence of success six years in.

Inside the rocky rollout of Denver Public Schools’ new school closure policy

Another policy Boasberg and the Denver school board created to guide its portfolio strategy was the “School Performance Compact.” Boasberg insisted the school closure policy was not the leading strategy to try to achieve the district’s improvement goals. The policy, he said, took a back seat to initiatives such as better coaching for teachers and improved reading instruction for young students. Instead, Boasberg described the policy as “a little bit of a safety mechanism” to be used when “these strategies don’t work and where over a period of time, kids are showing such low growth that we need to have a more significant intervention.”

Denver Public Schools retooling equity measure, presses forward on scoring schools

Denver’s well-established – and sometimes controversial – school rating system got an update in 2017 when the district added a new “equity measure.” Despite some pushback from school leaders, Boasberg and the district pushed forward with scoring schools based on how well they closed the gap between students who performed well on state tests (usually white and middle-class) and those who didn’t (usually black and Latino from low-income homes.)

Denver schools chief: Removing DACA protections for undocumented immigrants would be ‘catastrophic’

Boasberg took on a new role in the Trump era. The typically reserved superintendent regularly sought to reassure students, parents, and his own employees that he would protect them from any apparent overreach by the new administration. He also regularly spoke out in favor of Congress protecting the so-called Dreamers, undocumented immigrants who were brought to the U.S. as children. “Our schools and our community are strengthened by our city’s rich diversity and open arms,” Boasberg said. “The DACA program has helped bring wonderfully talented and critically needed teachers to our classrooms and has provided peace of mind and legal status to thousands of immigrant children and families who make our city and our schools great.”

Large achievement gaps in Denver highlighted by new national test data

Despite years of change, Denver’s achievement gap has barely budged. That fact was reinforced earlier this year after DPS received its scores from the tests known as “the nation’s report card.” At the time Boasberg said the latest scores confirmed the district needed to continue to focus on closing its gaps. He repeated his concern about the gaps when he discussed his exit with Chalkbeat.