Armstrong was born in the rural Victorian town of Kyneton in 1879, the eldest son of John and his wife Amelia (née Flynn).

By 1893, he had found himself a spot in the school XI and came to the attention of the press, catching the eye of journalists Reginald Wilmot and Tom Horan.

For the next twenty years, on and off the pitch, Armstrong's fortunes were tied to the club, a leading cricketing light in Australia and a bastion of the city's rich and powerful.

[12] He scored his maiden first-class century, 118, against South Australia, facing the very fast and physically dangerous bowling of Ernie Jones, and by the end of the 1900–01 season he was a permanent member of the Victorian team.

The English were considered a poor and undermanned team, but it surprised all by winning the first Test at the Sydney Cricket Ground by an innings and 124 runs.

[24] The 1905 Australians left for England, leaving behind the beginnings of a conflict between players and administrators over control of cricket that would poison the sport in Australia for the next ten years.

[30] Armstrong, finding himself promoted to number five in the batting order, started the tour well with 112 against Nottinghamshire and 248 against Gentlemen of England at Lord's.

Bumbling and taciturn, Armstrong maintained an accurate line and length, and put a strangle on both England's run-scoring and the crowd's entertainment.

Batsmen like the imperial Archie MacLaren would kick the ball away contemptuously, but lissome Johnny Tyldesley proved that runs could still made if a batsman employed more enterprise.

Hopping away to leg to make room for himself, Tyldesley cut and drove the leg-spinner to great effect in a strategy later used by Don Bradman against the bodyline menace.

[35] In the midst of all this turmoil, Armstrong continued to impress: on tour with Melbourne Cricket Club in New Zealand, he was described by that country's Herald newspaper as a "team almost in himself".

[36] He was elected captain of Victoria by his teammates for the match against New South Wales, commencing on New Year's Eve, responding with six for 68 with the ball and then scoring 168 in the second innings as part of a sturdy rearguard effort.

[37] The scheduled tour postponed from the previous season kicked off with the arrival of an English team weakened by the withdrawals of a number of leading players.

It then mounted a campaign in the Melbourne press, attempting to portray Armstrong as avaricious and once again called him to front a disciplinary commission.

[44] Regardless, the tour was a success, both for the Australians, who won the series two-one, and for Armstrong, who made 1,451 runs at an average of just under 44 and took 133 wickets at an average of 16.40[45] Wisden Cricketers' Almanack described his role in the tour as "to keep the side together by means of his impregnable defence, and he did exactly what was required, only on rare occasions giving free play to his hitting power.

[46] Armstrong, along with Monty Noble, Tibby Cotter and Bert Hopkins returned home via Sri Lanka (then Ceylon), Penang and Singapore, where they were lavishly entertained and comfortably billeted by the elite of the Colony.

[53] Returning to cricket after his self-imposed exile, Victor Trumper was the leading player for the Australians during the series scoring 661 runs at an average of 94.

[55] While this series took place, the Board of Control made plans to usurp the commonly accepted rights of the players to appoint a manager when touring England.

[57] When the Board announced that George Crouch would be manager of the Australian team for the 1912 Triangular Tournament in England, rather than the player's choice, Frank Laver, outright rebellion ensued.

Armstrong, Hill and Trumper, along with Hanson Carter, Tibby Cotter and Vernon Ransford (known as the "Big Six") announced that they would be unavailable to join the touring party.

[56] The tour was not a success on any front: the Australians winning only eight games and losing nine in a wet season and Crouch on return to Australia reported to the Board that "some of the players had conducted themselves so badly in England as to lead to the team being socially ostracised.

[61] The touring English team, captained once again by Johnny Douglas was no match for the Australians, who won all five Tests in the 1920–21 series, completing the first and only Ashes whitewash for 86 years on 1 March.

[70] Throughout the tour, Armstrong fought a series of running battles against the Board appointed manager, Syd Smith, on behalf of his men.

Armstrong resigned from his job with Melbourne Cricket Club and drawing on contacts he had made while on tour took a role as an agent for Dawson's Scotch Whisky.

[83] In July 1913, he married Aileen O'Donnell, the daughter of a wealthy Irish Australian pastoralist with large land holdings in the Riverina region of New South Wales.

[96] His pose at the wickets gives an impression of awkwardness which is not dispelled when he shapes to play the ball and his strokeplay is essentially laboured ... His methods, however, are remarkably effective; they show a most admirable blend of aggression and caution, backed by the right temperament.

"[97] It was effective, however, with the Daily Telegraph stating after the first Test in 1921, "there is not a single batsman in England who faces with any appearance of confidence his innocuous slows.

"[97] Armstrong was renowned for his gamesmanship and was willing to push the boundaries of what was considered acceptable behaviour in order to obtain an advantage for his team.

Armstrong was not a "walker"; he believed in waiting for the umpire to make a decision, once telling the English cricketer Arthur Gilligan, "The more you play this game, the more you will find out that you will be given out many times when you are not out and vice versa".

Jack Hobbs, describing one instance said, The chief offender was Warwick Armstrong, who got very nasty and unsportsmanlike, refusing to accept the umpire's decision.