Adrian Thomas Holdstock was born in Cape Town on 27 April 1970. Before his time in the middle as an umpire, he pursued a playing career in South African domestic cricket. He represented Western Province from the 1989/90 season through 1992/93, followed by a stint with Boland from 1993/94 to 1995/96. During his 16-match playing career, he scored 573 runs at an average of 20.46, with a top score of 81 and three fifties. With the ball, he took 19 wickets at an average of 33.78, recording best figures of 4/51.
Transitioning to officiating, Holdstock made his List A debut in 2006 and his first-class debut in 2007. He is currently an ICC international umpire and sits on the Cricket South Africa panel for first-class matches. His international presence began with his T20I debut in 2011, followed by his first ODI appearance in 2013. By March 2023, he reached the Elite Panel of ICC Umpires alongside Ahsan Raza.
Over his career, he has stood in 21 Test matches between 2020 and 2025, beginning with the South Africa versus Sri Lanka clash on Boxing Day 2020. His white-ball officiating includes 66 ODIs from 2013 to 2026 and 60 T20Is spanning 2011 to 2026. He also officiated in 17 Women's ODIs between 2009 and 2018, as well as 7 Women's T20Is during 2009 to 2019.
His involvement in major tournaments includes selection for the 2020 Under-19 Cricket World Cup, the 2021 ICC Men's T20 World Cup, and the 2023 Cricket World Cup. Throughout his time in the game, he has balanced his domestic responsibilities with his work on the global stage.