Chisholm has also been a key figure in Wallaby selections since making his Test debut – replacing Nathan Sharpe – on the 2004 Spring Tour and passed 50 Tests in 2010. The following season he made his debut for the Wallabies in a test against Scotland in Edinburgh and was subsequently named in the 22 against France the following week and went on to start at lock for Australia A against the French Barbarians in Paris. In 2005 he started at lock in six of the 12 tests he played in. He also scored tries in the tests against Samoa and Italy. He was named in the Wallabies 2007 Rugby World Cup squad. He is the 32nd Australian player to play in a half century of Tests, and just the fourth lock. He finished the 2010 Super 14 season just 12 matches short of a century of matches in that competition. He was ruled out of competing in the 2011 Rugby World Cup due to rupturing his anterior cruciate ligament in a Super Rugby match for the Brumbies in June 2011.
In December 2004, he married his childhood sweetheart Lauren Campbell with the blessing of her father, former Wallaby second row Bill Campbell, at All Hallows in Brisbane. They have 5 children together; Zachary, Xander, Allegra, Tobias and Olivier.