Cunningham was born into a rather famous family tree with grandfather Thomas being a New Zealand whaler, trader and founding father; aunty Kate Wyllie (nee. Halbert) was a New Zealand tribal leader; uncle Otene Pitau was a New Zealand Māori leader; uncle Wi Pere was a Māori Member of Parliament; sister Reremoana Hakiwai was a New Zealand cook and community leader, among many other relatives from future generations like author Witi Ihimaera, Museum of New Zealand Te Papa Tongarewa's curator Arapata Hakiwai and former All Black Tu Wyllie.
One of 'The Originals' in 1905-1906 that toured Britain, Cunningham moved to Waihi at a young age.
He played his rugby for Waihi West who were then under the boundary of the Auckland Rugby Football Union.
Cunningham moved to Auckland in 1902 and represented the City (Auckland) and Ponsonby clubs.
He played for Auckland from 1899 until 1913.
Cunningham was a lock, considered to be a "powerhouse scrummager", although he was just 180cm tall and 92kg – a big man for the time.
He made his debut for New Zealand against Wellington in 1901 at age 27 but his international debut wouldn't come for another four years, against Scotland at Edinburgh.
Cunningham wasn't selected for New Zealand in 1904 but continued to appear for Auckland.
This was the year of the first Ranfurly Shield match.
Due to Auckland's unmatched provincial record at the time they were given the shield.
The first shield challenge was against Wellington, and although Auckland had not lost at home in six years, Wellington defeated them 6-3, forfeiting the shield.
The same season, Cunningham and Auckland defeated the British Isles 13–0, with Cunningham scoring a try.
As "The Originals" were formed in 1905, Cunningham was recalled to the New Zealand squad.
They set off on-board the Rimutaka, for a six-week voyage to the British Isles.
"The Originals'" played 35 games on their tour and lost only one. Cunningham took the field in 23 of these.
New Zealand scored 976 points and conceded 59, still today known as one of the greatest ever All Blacks sides.
Cunningham played 39 All Blacks matches (1901-1908) which included nine tests, playing prop in one and lock in the other eight, scoring one try.
His total of 22 All Blacks points (matches and tests) consisted of two tries and eight conversions.
A goal kicking lock, something that Wallaby John Eales normalised almost a century later, Cunningham also represented the New Zealand Māori side between 1910 and 1912.
It was said by plenty of other players that "there was none like Cunningham".
In Lindsay Knight's biography of Cunningham for the New Zealand Rugby Museum it said:
"With his 45 games for Auckland, 39 including nine internationals for his country and matches for North Island (1902 and 1908) and for New Zealand Māori Cunningham finished with the rare feat for a player of his times of more than a century (103) of first class games.
"Cunningham was noted for his cheerfulness and his determined optimism.
"Once when he had given chase to a noted sprinter in a vain attempt to stop a try he was asked by his teammates as the conversion was being taken why he had bothered when his task was so hopeless. 'Because,' replied Cunningham, 'he might have dropped dead'."
George Gillett, a former New Zealand rugby and rugby league player, also from the Waihi area, had stated that Cunningham was a tough player.
"Our old friend Bill Cunningham, and a number of other old players I could mention, would scorn the idea of any medical attention on the field of play and would pass caustic remarks to others who availed themselves of such attention."
In 1907, during his international career, Cunningham had married Ethel Minnie Dance of Waihi and the same year, their only child William Henry Cunningham was born. Sadly, he passed away at 1-day-old.
Cunningham wasn't just a rugby player; he had also been an axeman, a miner and a freezing works labourer – all which would have pushed his case as a strong scrummager.
On September 3, 1927, Cunningham passed away from acute meningitis. At the time he was working at an Auckland freezing works.
Members of the New Zealand, Auckland, New South Wales and Thames Rugby Unions attended Cunningham's wake while 1890s New Zealand representative Fred Murray, and fellow 'Originals' Gillett, George Tyler and George Nicholson were the pallbearers for their fallen friend.
Cunningham was laid to rest at Hillsborough Cemetery, one of the oldest cemeteries in Auckland, which overlooks the Manukau Harbour. He was 52 years old.
An Auckland rugby jersey was thrown on top of his casket, a representation of his service and commitment to the jersey and region – buried with his colours.