Appiah made his professional debut for Nottingham Forest on 30 October 2018, appearing as an 85th-minute substitute and scoring a goal in a 3–2 loss in a fourth round EFL Cup game against Burton Albion.
[4] On 2 September 2019 Appiah signed for Spanish Segunda División side Almería on a five-year deal for an undisclosed fee, reported to be £8 million.
[5][6][7] On 1 February 2021, Appiah moved to fellow second division team CD Lugo, on a loan deal until the end of the season.
[9] On 30 December, however, his loan was cut short,[10] and he moved to fellow second tier side Málaga CF on 9 January, also in a temporary deal.
[16] In March 2019, Appiah received his first call-up for the England U19s for the 2019 U19 EURO Elite Qualifying Round[17] and made his U19 debut as a 66th minute substitute during the 4–1 win over Czech Republic at St. George's Park.