The 24-year-old joins Palace on a three-year contract ahead of our return to the Barclays Women’s Super League.
Born in Coventry, O’Brien began her career at Aston Villa before joining Coventry United (now Rugby Borough) in 2018.
Six goals in 21 appearances earned her a move to Leicester City in January 2021, where she helped the Foxes seal promotion at the end of the season.
O’Brien was a constant figure throughout Leicester’s five-year tenure in the WSL - making 97 appearances and scoring 17 goals in all competitions.
The former England Under-23’s player was Leicester’s top goalscorer last season – netting five goals in 21 WSL appearances.
O’Brien becomes Palace’s fifth signing of the summer window, joining Sierra Enge, Bethany England, Teyah Goldie, and Lexi Lloyd-Smith in Manager Jo Potter’s new-look team.
Potter said: "It's great to have Shannon join us.
"Despite being just 24, she has been an important player in the WSL for several years now and we are delighted that she has chosen Palace."
Upon signing, O’Brien said: “I’m really excited to be here!
“It’s a big club and we deserve to be in the top league, so I'm looking forward to the season and to the challenge ahead.”
