Serge Buttet was encouraged by his father to join the Dauphins romanais péageois swimming club when he was eight years old. During the 1970s Buttet won the French title in the 100 metres butterfly on seven occasions. In 1974 he finished in eighth in the final of the 100 metres butterfly at the European Swimming Championships in Wien. The following year he swam in the same event at the 1976 Montréal Olympics where he was eliminated in his heat. After his retirement in 1978 Buttet worked as the technical advisor at the Departmental Directorate of Youth and Sports in Bordeaux. A swimming pool was named after him in his hometown of Romans-sur-Isère in 2020.