Danaher is the longest-serving player at the Exiles, with the 32-year-old having joined in 1999.
Since then, Danaher has gone on to make 240 appearances for the club - winning caps for Ireland at Under-19s and U21 levels as well as for England U21s and A team.
And Danaher, who had previously had trials at Queen's Park Rangers, is determined see the club win silverware over the course of the next two seasons.
He said: "I have only played for London Irish throughout my career and have no desire to play for any other club other than this one.
"I am passionate about the Exiles and feel that we have a lot of unfinished business in terms of bringing silverware back home and that's something I want to be part of."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.