The 18-year-old’s selection follows his under-19 ‘Test’ debut during England nine-wicket win against the tourists earlier this week.
The squad for the one-day series includes 13 members of the ‘Test’ squad and two newcomers: Jordan Cook, an off-spinner from Nottinghamshire; and Jamie Smith, a batsman from Surrey.
Jon Lewis, the Young Lions head coach and Sussex’s former assistant head coach who joined John Abrahams and David Graveney on the selection panel, said: "The focus for our players remains on four-day cricket, with our second 'Test' at the Emirates Riverside starting on Monday. But the three-match Royal London One-Day Series is just as important in terms of giving our young players experience of international white-ball cricket - especially with the first game of the series being shown live on Sky Sports, which will be a new experience for the majority of our squad.
"As with the selection of the four-day squad, we have followed a policy of allowing players who are gaining regular first-team experience in county cricket to stay with their counties. The performances of guys like Harry Brook, Henry Brookes, Will Jacks and Dillon Pennington this season are so encouraging for all of us who worked with them on the Young Lions programme over the last couple of years, to see how they're kicking on.”
England Under-19s squad for Royal London One-Day Series against South Africa
Liam Banks - Warwickshire
Tom Banton - Somerset (captain)
Ben Charlesworth - Gloucestershire
Sam Conners - Derbyshire
Jordan Cook - Nottinghamshire
Jack Davies - Middlesex
Adam Finch - Worcestershire
Alfie Gleadall - Derbyshire
Jack Haynes - Worcestershire
Luke Hollman - Middlesex
Nick Kimber - Nottinghamshire
Jack Plom - Essex
Ollie Robinson - Kent
Jamie Smith - Surrey
Harrison Ward - Sussex
The ODI matches take place on 23rd July (Emirates Riverside), 26th July (South Northumberland CC) and 29th July (Scarborough CC). All start at 11am, with the first to be shown live on Sky Sports.