Parknasilla made his debut in September 2002 at Beverley, and showed little until his third outing when he was runner up in heavy ground at Doncaster. He won his first race at the age of three in a Southwell seller.
Reaping the benefits of his favourite soft ground and a longer trip, he was a 20/1 winner over hurdles at Leicester in January 2004. Four consecutive placed efforts followed, before he was a winner over fences at Wetherby in his five year old season. He had won three times, once on the flat, once over timber and once over fences. Parknasilla was retired in 2005.