Lofton, who has been largely credited with Senn's transformation in the past three years, said she's "extremely happy" to continue her work at the school.
"While we have begun a lot of good work here, we are by no means finished," Lofton said Friday afternoon. "We have an overall vision to really set a model for neighborhood schools."
Local School Council member Dan Kleinman said he and his colleagues on Thursday signed off on a four-year extension of Lofton's contract, which will carry her tenure into 2018.
"She came in at a very difficult time and the school needed a cleanup and a resurgence of energy — and she brought that," he said. "This new contract will give her flexibility to bring it to the next level."
Since she was hired in 2010, Senn High School's ranking has moved from among the bottom third of Chicago Public Schools to the top tier. Senn earned a level 1 (excellent) rating from Chicago Public Schools this year after being on academic probation 13 of the last 17 school years, according to district data.
The school's rating, calculated with a variety of metrics including test scores, attendance rates and drop-out rates since 2009, shows steady improvement. The school has expanded its rigorous International Baccalaureate program, in which all new students now are enrolled, and has added science and computer labs, a dance studio and renovated its auditorium.
But while measures of academic success at the school still haven't reached district averages, officials and community members say it's the culture at the school that has seen the biggest change.