The former Arsenal trainee, who enjoyed a successful loan spell from Derby County towards the end of last season, tied up the lose ends at The Den to complete a move from the Premiership new-boys for an undisclosed fee.
The move had been on the cards for some time but in order to free up the necessary funds for the player, manager Willie Donachie had to cut his cloth accordingly and lost Tony Craig as a result. But the Lions boss couldn't hide his delight when speaking to the club's official site about his new player.
"He is an excellent acquisition for us," said Willie. "Ryan has great talent, speed and is an exciting player with real potential."