The midfielder, who turns 34 in August, will take the armband for the 2019/20 season in the English League One. 

Milligan most recently played last season for Hibernian in the Scottish Premiership and captained the Socceroos at the 2019 AFC Asian Cup. 

"I'm very pleased and i's a nice responsibility." Milligan told Southend United. 

"It's not something we've spoken about a great deal but it's something that I will take very seriously.

"I've been fortunate enough to be captain of a number of teams that i've been at and hopefully my experiences over my footballing journey can help here." 

As well as captaining Australia, Milligan has worn the armband at Melbourne Victory in the A-League and for Baniyas in the UAE.