Albert Pierrepoint hanged a record number of individuals between 1932 and 1956. Although the precise number is still unclear, popular estimates place it at 435, but the man once asserted 550. As a young child, he was inspired by his father and uncle, both of whom carried out executions, and helped his uncle in the early stages of his career.
Source Materials:
https://allthatsinteresting.com/albert-pierrepoint
https://www.sussex.ac.uk/broadcast/read/32976
https://www.lancs.live/whats-on/pierrepoint-preston-pub-owner-who-16407483
https://www.thefamouspeople.com/profiles/albert-pierrepoint-50229.php
https://www.bbc.com/news/uk-england-berkshire-65562086
https://www.theguardian.com/lifeandstyle/2010/sep/18/albert-pierrepoint-ian-sansom
https://headstuff.org/culture/history/the-pierrepoints-a-deadly-family-business/