Fountain, 25, is a former fifth-round pick of the Colts back in 2018. He signed a four-year, $2.7 million contract with the team, but was waived at the start of the 2018 season.
The Colts later re-signed Fountain to their practice squad and eventually promoted him to their active roster towards the end of the 2018 season.
Indianapolis then re-signed Fountain to an exclusive rights free agent deal in 2020. Fountain spent the season bouncing between the Colts practice squad and active roster.
The Chiefs signed Fountain to a one-year deal in May.
In 2020, Fountain played in six games for the Colts, recording two catches for 23 yards.