Long was runner-up in the 2018 English Amateur, losing, 6 and 5, to Thomas Thurloway in the final.

[1] In the 2020 English Amateur, he led after the stroke-play stage to be ranked as the top seed going into the match-play;[2] he was ultimately knocked out in the quarter-finals at the 23rd hole.

[3] Long won the 2020 Amateur Championship at Royal Birkdale, beating Joe Harvey, 4 and 3, in the final.

[4][3][5] Long was selected for the 2021 Walker Cup, but only played in the final-day singles session due to "gastrointestinal issues" that impacted both teams.

In August 2022, Long finished runner-up at the Vodacom Origins of Golf at De Zalze, two shots behind winner George Coetzee.