Ireland

Easterby made his first international appearance in a Six Nations victory over Scotland at Lansdowne Road in 2000 and then became a regular in the side, being ever-present for the remainder of that Six Nations competition. Easterby then played in all three of the games during the summer tour but he missed all of the following season due to injury and did not return until the game against Scotland in September 2001. After Ireland's defeat, he lost his place but he did win a cap as a replacement against Samoa in November 2001. In 2002 he played a part in the first ten of Ireland's games – eight as a starter – but after that, he lost his place and he did not return until playing in two Tests during the summer tour of 2003 against Tonga and Samoa.

He was virtually ever-present for Ireland since then; he has received in total 65 caps and scored 40 points. Described as the "elder statesman among Ireland's back-row options" in 2007, one newspaper suggested that "[2007] could well be Easterby's last Six Nations campaign"^[4] As it turned out, Easterby played in one more Six Nations Championship in 2008, after which he retired from international rugby to concentrate on his club career.^[5]

British & Irish Lions

Easterby received a call-up to the 2005 Lions tour to New Zealand, after Lawrence Dallaglio fractured his ankle in the first game of the tour. He forced his way into the Test team and covered himself in glory, including scoring a try in the second Test in Wellington. He took over the leadership duties for the 2005 Autumn series in the absence of injured duo Brian O'Driscoll and Paul O'Connell. In total he has two British & Irish Lions caps.