[1] A flanker, and later hooker in rugby union (with Souths), when in 1902 Hennessy represented against New Zealand, the All Blacks mistook him for a halfback as he lacked the size they deemed necessary for a forward.

When the new game of Northern Union (rugby league) arrived in Australia in the late winter of 1907, he enthusiastically stepped on board and when the New Zealand All Golds came to play the first of their historic three-game series against the locals at the Agricultural Ground (Sydney Showground) in August 1907, he was the NSW captain and coach.

[3] In July of that inaugural season he made another representative appearance captaining New South Wales in a 43-0 whitewash of Queensland in the first ever Australian interstate match.

[1] In 1909 Hennessy made three appearances for the Eastern Suburbs club, including that year's semi-final against Balmain in which he was named as captain.

Jack Coyne summed him up this way: "His outstanding coaching ability, his leadership on the field and off, his pertinacity and his personality all combined to make Arthur a redoubtable friend and an implacable opponent."

Coyne made the point that for a footballer to survive the challenges that emerged in rugby league's early days, he had to be "a big man, in heart, courage and stature".

As coach at South Sydney he was also the father of the Rabbitoh's own style – introducing the famous "no kick" policy, based on his football creed of Position, Possession, Penetration and Pace.

Souths lived that creed through glorious eras and for much of the club's life – although the arrival of the limited tackle rule in 1967 inevitably changed the way the game was played.

In 1913 he coached a New South Wales side on a tour of New Zealand and was ahead of his time in introducing a steak-only protein diet on match days.

[1] Hennessy joined the 1929–30 Kangaroo tour of Great Britain as coach-masseur of the Australians,[4] who due to Chimpy Busch's controversial 'no-try' at Swinton, were unlucky not to bring home the Ashes.