Ioannidis grew up in the Ringoes section of Raritan Township, New Jersey and attended Hunterdon Central Regional High School.

[1] The middle of three boys, Matt and his brothers Andrew and Kevin, grew up playing football, basketball, and lacrosse.

[10] In 2018, Ioannidis played in 14 games with nine starts, recording 31 combined tackles, a forced fumble, and 7.5 sacks, which finished third on the team.

[18] He played in and started 13 games during the 2022 season and recorded 37 tackles, 1.5 sacks, 1 pass deflection, and 1 forced fumble.

In September 2024, it was announced that Ioannidis was hired by Mechanicsburg Area Senior High School as an assistant defensive line coach.