Malcolm Green said the authority "is now determined to move on and to make sure that the image of the school actually reflects what is happening within it".
Jean Murray, who was head for two years, has taken early retirement at the age of 50. She said she had been "forced out".
Claims that Shawlands, which has 600 Asian and 800 white pupils, is "a powderkeg of racial tension" have been vigorously dismissed by the council. A 15-year-old Asian pupil was killed outside a Shawlands chip shop earlier this year and two other Asian pupils face murder charges.
Dr Green said the council would investigate reports that consistent opposition to Mrs Murray from a group of "anti-racist" teachers, particularly over disciplining Asian pupils, led her to throw in the towel.
He pointed out that 10 members of staff were from the ethnic minority community, including the new acting depute and the head of guidance, more than any other secondary in Scotland.