The 30-year-old former Dagenham & Redbridge captain arrives at Crabble after leaving National League South side Billericay Town.
The defender, who will wear the number 26 shirt, started his career with AFC Newbury before joining Swindon Town in 2005.
After being released by the Robins, he joined then-Conference National side Weymouth in 2007, making 63 appearances..
Doe made the move to Dagenham in February 2009 and went on to play 243 times, scoring 11 goals, in his first spell.
He moved to Boreham Wood in July 2015 and then re-joined the Daggers following their relegation from the Football League.
In all, Doe made 327 appearances in his two spells with Dagenham, including the 2010 Promotion Final at Wembley before he left in February 2018.
He then had spells at Whitehawk and Boreham Wood before joining Billericay.