"Happy to sign with Liverpool FC," Scanlon wrote on his Instagram account on 23 December 2020. "A big thank you to BCFC and everyone who has helped me progress to this point, but as of today I start a new chapter. The hard work continues, let’s go!", the 15-year-old concluded. Thirty-four months later in October 2023 Scanlon made the bench in the Merseyside derby in the Premier League, a clear sign of his progress through the ranks. The following week he made his debut, coming off the bench in the second half in a Europa League group stage game at home to Toulouse. In August 2024 he joined Millwall on a season long loan, but suffered a stress fracture in his back in September. This was expected to rule him out for three months and he returned to Liverpool for treatment.