Donald Day III joined the Case Western Reserve University coaching staff as an offensive assistant prior to the 2022 season after his four-year career at running back for the Spartans. After serving as an offensive assistant in his first year, he was named the Running Backs coach entering the 2023 campaign.

A semifinalist for the William V. Campbell Trophy as a senior in 2021, Day finished his career with 758 rushing yards and eight touchdowns, while catching 30 passes for 210 yards and a touchdown. He was a multiple-time UAA All-Academic honoree and PAC Honor Roll recipient over the course of his career.

Day graduated from CWRU in 2022 with a bachelor's degree in biology.