Eighteen years ago, on his first day of work at Brookline High School, Adrian Mims knew he had ventured a long way from Spartanburg, S.C.
As he walked into the school where he had been hired as a $9-an-hour math tutor for METCO students, he spotted a banner for the school's Gay-Straight Alliance.
"I loved it," he says. "Not because I'm gay — I'm not — but because of the respect for differences. That was the opposite of what I had experienced and it was wonderful."
Over the years, Mims steadily climbed from tutor to math teacher to department head to dean, a post he has held since 2007.
But then things soured. Mims is now the plaintiff in a complaint to the Massachusetts Commission Against Discrimination that alleges he was passed over as headmaster of Brookline High School because he is black.
Mims's complaint has roiled Brookline, a liberal bastion where inclusion is assumed to be a given.
Mims, 41, has spent his entire educational career at the school. His signature initiative has been the African-American Calculus Project, a tutoring program designed to increase the number of minority students in the school's calculus classes. When he began the program, that number stood at zero. Based on the underclassmen in preparatory classes, he projects that 12 students will be taking calculus in 2014.
Mims moved to Boston almost by accident. When he graduated from the University of South Carolina, his future wife was interested in taking classes at Harvard Extension School, as preparation for medical school. He was open to leaving the South.
One controversy in particular came to symbolize his frustration with his native state. "When I was in college, the big controversy was over the Confederate flag flying over the state capital," he said.
Brookline High, he says, is everything his high school was not — full of ambition and diversity. When longtime headmaster Robert Weintraub retired, Mims thought he had a great chance at the job. He had a strong relationship with Weintraub, was a dean, and held a doctorate, which the job posting said was"preferred."
But in February, he was informed by Superintendent Willliam Lupini that he would not be a finalist.
"He came and met with me," Mims said. "He told me, 'You're an incredible talent. You can go anywhere you want. You can be a superintendent.' It was almost like he was apologizing for [passing] me over."
By law, superintendents — in this case, Lupini — have near-total control over appointing principals and headmasters. Part of Mims's complaint is that the process was not open or transparent, and was tailored to candidates Lupini favored. Mims also said he was told that one search committee member expressed the view that Brookline High was "not ready" for a black headmaster.
Lupini eventually named Deborah Holman, vice principal of Newton North High School, as Brookline's new headmaster. Holman does not have a doctorate.
Lupini said Friday that he couldn't comment on the specifics of Mims's complaint, though he did praise him generally. "I can tell you that Adrian has been involved in a number of terrific initiatives, among them the Calculus Project. He's been intimately involved in that and done terrific work."
Mims has no plans to leave the school, and his affection for it remains evident. But, he said, "In this particular situation, I feel like the rug was pulled out from under me."
Adrian Walker is a Globe columnist. He can be reached at email@example.com. Follow him on Twitter @Adrian_Walker.