Dominic Ballard has joined the Robins in a four-year deal for an undisclosed fee from Leyton Orient.
The 21-year-old forward, who netted 23 goals in 40 league appearances last season and won the League One Player of The Season becomes their eighth signing of the season.
Michael Skubala had previously expressed a desire to enhance forward positions with “pace and power.”
Sporting director James Ellis said: “Dom is only 21 years old and already has a proven record of scoring goals.
“He has a big future ahead of him and we’re and we’re excited to see how he develops over the coming years.
“Along with our other front-line players, we now have options for Michael and his staff to have different approaches and selections where required in what will be a highly competitive season.”
Ballard smashed in 23 goals in 40 league games for Leyton Orient last season, despite the team finishing just one place above the relegation zone.
Ballard made his senior debut for Southampton with a goal against Cambridge United in the EFL Cup as a 17-year-old in 2022.
Scoring five goals in 12 appearances for Reading in 2023/24, the youngster has played in League One for Cambridge United and Blackpool.
Ballard has an injury-hit loan spell with the Royals, his first major spell in the first-team since breaking through at St Marys. A patella injury ruled him out for more than half of 2023/24 as Ruben Selles’ Royals finished 17th in League One.