Monroe served Northside ISD for 29 years of his 30 years as a distinguished educator. He was a classroom teacher at Cable Elementary, Westwood Terrace Elementary, and Rayburn Middle School, as well as a counselor at Westwood Terrace. He was selected on two occasions to open new elementary schools as Principal, first at Meadow Village Elementary and later at Shenandoah (now named Howsman) Elementary. In 1972 May was named the first Director of Elementary Education in Northside ISD. He held that position, which involved providing both administrative and instructional leadership to District elementary schools, until his retirement in 1990.
May was highly respected by teachers, principals, district staff, and parents with whom he worked because of his clear interest of students, his friendly manner, and his professional expertise. He visited campuses and classrooms frequently and established a reputation among campus staff as knowledgeable and supportive of campus programs.