M'Baye Niang was born on 19/12/1994 in Meulan-en-Yvelines, France. He joined Caen's youth academy at the age of 13. On 27 August 2012, it was confirmed that Niang was in negotiations with Italian club Milan. On the following day, the move was confirmed. In January 2014, Niang joined Montpellier on loan. In January 2015, Niang was loaned to Genoa for the remainder of the season, before being sent back to Milan. In January 2017, Niang was sent on loan to Watford. On 31 August 2017, Niang signed for Torino. On 31 August 2018, Niang joined Rennes.