Hanks has worked with Wasps before, first joining the club as a technical analyst and assistant coach under Lions forward coach Warren Gatland in 2002.
Hanks enjoyed three hugely successful years at Adams Park, winning three Premiership titles, a Heineken Cup and Parker Pen Shield before moving to Waikato as assistant coach in 2005. He went on to work for the Chiefs in the Super 14 and for the Junior All Blacks and was promoted to head coach at Waikato in 2008.
The New Zealander then had a second spell with Wasps between November and April of this season, supporting McGeechan and Lions defence coach Shaun Edwards.
"I feel very privileged to be appointed as director of rugby of London Wasps," said Hanks.
"I follow two pretty special coaches in Warren Gatland and Ian McGeechan - two guys that I have a huge amount of respect for.
"I feel very honoured to follow in their footsteps and I am thankful that I have not only had the opportunity to work with them but to learn from them both as well.
"I came to Wasps in November with every intention of going back and resuming my Waikato commitments but the Wasps role was an opportunity too good to turn down.
"When I left Wasps I always said that it would be great to be able to come back in some sort of capacity and what better than as director of rugby? Wasps is a well respected club beyond the realms of the Northern Hemisphere and I am and always have been excited by the challenges that the Premiership and the European competitions bring."
Edwards, who will himself stay on as head coach at Wasps coach for the 2009/10 campaign, praised the appointment of Hanks, saying that he expects the Club to go on to even greater things in the coming years.
"Wasps is a family, that is what we pride ourselves as and it is true of the past and of the future," explained Edwards.
"We have a saying, 'Once a Wasp always a Wasp', and Tony Hanks was an integral part of our success when Warren was in charge. The three of us were not only pals off the field but very successful on it and he is one of very few coaches who have enjoyed success in both hemispheres.
"He's a bloke I have continued to be in constant contact with during his time at Waikato. He always text me throughout the years he hasn't been involved at Wasps - after every big game, or virtually every game to be honest, saying good luck or good win, so I have been in constant contact since he left and I am pleased he is back on a full-time basis.
"He did a great job last season coming in and basically helping us to try and turn our season round after a horrific start. During the November and December games, when we were missing a lot of players, I thought the team did exceptionally well and benefited form the extra coaching strength Tony brought.
"I think from late November to the end of the season the team averaged 3 points a game and had we had that form throughout the whole of the season we certainly would have had a top-end of the table finish.
"We welcome Tony back into Wasps and I am looking forward to the next few years where hopefully we can continue to be a power in the Guinness Premiership and the European competition with him leading from the front."