 On 4 September 2019 Jefferies made his debut for Newport County in the starting line up for the 5-4 defeat to West Ham United Under-21s in the EFL Trophy Southern Group E.

On 21 January 2020 Jefferies joined Salisbury on a one month loan.He scored his first goal on his debut in a 5-0 win over Dorchester Town on 27 January 2020.Jefferies was recalled from his loan at Salisbury on 18 February 2020 to cover an injury crisis at Newport.