Played for Newport RFC from 1927-28 to 1930-31, making his debut aged just 17. Awarded six Wales caps 1929-30 - debut try against Scotland at Swansea in 1929 (Wales 14 v 7 Scotland). 'Shared' a try touching down jointly with Howie Jones (Neath) against Ireland in 1930 at Swansea (Wales 12 v 7 Ireland).

In his book "Rugby Recollections" W. J. T. Collins said of Peacock "In 1929 and 1930 among the forwards who played their parts manfully were Cecil Pritchard (Pontypool), who was in all eight games, and H. Peacock (Newport), who missed both the English games. The former was great in the front row, and Peacock, in the back row, was especially useful for his well-judged punting to touch."