Most recently at Stevenage, Schumacher played twenty-eight times in League Two last season along with two EFL Trophy appearances.
He started his career at Everton and captained the England under-19 side.
In his fifteen-year career, Schumacher has made 410 Football League appearances with Carlisle, Bradford City, Crewe Alexandra, Bury, Fleetwood Town and Stevenage.
Southport manager Alan Lewer said: “He’s a great signing for us. We were up early this morning trying to get that over the line. He had two league clubs contact him today but the good thing for us is he’s taken a coaching job at Everton with the youth team.
“He’ll bring goals hopefully. Once we get our shape right and he’s part of that shape, I’m sure there’s goals to come from him”.