"At Seventeen" peaked at number three on the September 13, 1975 on "Billboard" Hot 100 chart, and remained on it for twenty weeks. It reached number one on the Adult Contemporary "Billboard" chart for two weeks in August 1975, and stayed on the chart for fifteen weeks. It also peaked at number one on the "Cashbox" top 100 chart, and number six on its year-end pop singles chart. On the "Billboard" Year-End chart, "At Seventeen" ranked number nineteen. It also reached number twenty for pop and number two for easy listening. According to "Billboard", the song enjoyed a resurgence in sales after the Grammy Awards in 1976.