After defeating Lord Voldemort, many people assumed Harry would return to Hogwarts to complete his final year of studies. However, that never happened. Instead, he became an Auror.
Rather than returning to the classroom, Harry went straight to the Ministry of Magic to become an Auror. Thanks to his role in the war, an exception was made to the usual entry requirements, as he had repeatedly demonstrated the skills needed for the job.
Alongside Ron Weasley, he helped capture the last remaining Death Eaters who were still in hiding after the war. Over the years, Harry continued to rise through the ranks of the Department of Magical Law Enforcement, eventually becoming one of the most prominent Aurors of his generation.
Although he never returned as a student, Hogwarts always remained his home. He visited the castle and those who remained there on several occasions, but his time as a student had ended the night he defeated Voldemort. From that moment on, he chose to dedicate his life to protecting the wizarding world so that no one would ever have to endure another war like the one he had fought.