The 21-year-old joins the club after graduating from Arizona State University and has previous experience in the FA Women’s Super League with Doncaster Rovers Belles.
The versatile wide player will take the No.23 shirt for the Reds.
“I’m excited to have Jemma as part of our squad here at Liverpool FC Women. She will add to the depth of our player roster,” said LFC Women manager Vicky Jepson.
“She’s got international experience already and has youth very much on her side. She’s been training with us recently and has fitted in brilliantly with the rest of our squad.