 McGregor was subsequently selected for the 1903 New Zealand rugby union tour of Australia and won his first Test cap for New Zealand on 15 August 1903 against Australia.He transferred to Wellington in 1904 due to his employment taking him to Petone, there he joined the Petone Rugby Club and was later one of six players from the club that made the 1907-08 tour.McGregor represented Wellington and the North Island and retained his place in the All Blacks in 1904 and in 1905 was selected for the All Blacks tour of Great Britain.