31-year-old Williams last played for Wellington Phoenix in the Australian A-League where he forged a lethal partnership with fellow ATK recruit Roy Krishna. The pair bagged a total of 30 goals between them in the 2018-19 season with Williams himself accounting for 11 of them.
“I am happy to join ATK for the upcoming season of Indian Super League,” the Australian said on his move.
“I am absolutely delighted that I will be able to play alongside my friend Roy Krishna.
“Hopefully, together as a team, we will be able to win the title and create memories.”
The forward had represented Australia at the 2005 FIFA U17 World Cup in Peru and has also earned two caps for the senior national team. Williams has played in the A-League for the major part of his career with stints at Queensland Roar, Sydney FC, Melbourne City and Wellington Phoenix.
He has also undertaken two stints in Europe with Brondby in the Danish Superliga and with Haladas in the Hungarian League.
ATK head coach Antonio Lopez Habas has welcomed the forward’s signing and is expecting Williams to recreate his partnership with Krishna.
“David Williams is another signing I am very happy with. His pace and technique will be valuable to us,” Lopez stated.
“He also brings variety to the squad since he can play on either side of the wings as well. His understanding with teammate Roy Krishna will be crucial for us,” he added.