[1] Johnston took up cricket from an early age, playing with his elder brother Allan throughout the year on a backyard pitch on the family's dairy farm, owned by his father.

The following season, the brothers led Beeac's attack, continuing to do so after moving to Colac High School, where Bill became captain of the cricket and football teams and a prefect.

[2][3] Johnston joined the Royal Australian Air Force along with his brother, serving for four years as a radar technician in northern Australia.

[2][3] Prior to World War II, Johnston was a slow-medium and left-arm orthodox spin bowler, but during a practice session, he bowled a quicker ball to Jack Ryder a former Australian captain and Test batsman, who was now a Victorian and national selector.

[8] Although he dismissed Cyril Washbrook in the first over of Victoria's match against Wally Hammond's touring England team of 1946–47, he was sceptical about his pace bowling.

[5] In the same season, Colin McCool, Ian Johnson, Bruce Dooland and George Tribe had all played in Tests as specialist spinners.

[4] His best performances in the tour games included a match haul of 10/40 against Yorkshire at Bradford, bowling finger spin on a wet pitch, 8/68 against Somerset and 11/117 against Hampshire.

He took 3/47 and 5/62 and his wickets included future Test batsmen Jim Burke, Jimmy de Courcy and Jack Moroney, but was unable to stave off defeat.

The tour started badly; after taking a total of 5/28 in an innings win over Zululand in a non-first-class match,[6] he fell asleep at the wheel outside Durban following a team function.

[23] The team manager Chappie Dwyer was mistakenly informed that Johnston had died, and the bowler later described his injury as a "nine-iron divot in the top of my skull".

However, news was leaked back to Australia, and Johnston's mother fainted; her husband and other son had already died and she was fearful that her lone remaining relative had joined them.

[24] Keith Miller was called to South Africa as emergency cover,[24][25] but luckily for the Australians, there were almost two months of warm-up matches before the Tests started.

[12] South Africa had reached 2/242 in their first innings when Johnston removed their captain Dudley Nourse, precipitating a loss of 8/69 on a sticky wicket as the hosts were bowled out for 311.

[30] The entire first-class campaign was even more successful; Johnston took a total of 7/37 as the Australians ended their tour with an innings victory over a South African XI.

[31] In the opening match of the season for Victoria against the touring Englishmen, Johnston warmed up by scoring 30 and taking a total of 3/89, including the wickets of leading batsmen Compton and Hutton.

[12] Johnston started the series steadily with match figures of 3/90 in the First Test, removing vice-captain Jeff Stollmeyer and leading batsmen Frank Worrell and Everton Weekes as Australia scraped home by three wickets.

[6] He removed Barnes, Morris, Moroney and Miller, before returning to dismiss future Test teammates Richie Benaud and Alan Davidson.

The crowd of 30,000 and the constabulary were resigned to an Australian defeat, with the police officers moving into position to stop the customary pitch invasion at the end of the match.

[3][12] Ring thought that playing for a draw was impractical, so he decided to attack, while Johnston attempted to hold up his end with a series of defensive shots.

[6] After injuring his knee in a festival match at the beginning of the tour at East Molesey,[46] Johnston attributed the injury to a lack of attention to detail.

[6] He staked his claim for selection in the final two tour matches before the Tests; he took 4/65 and 3/49 against Sussex and then led the way in a win over Hampshire, much as he did five years earlier, taking 5/75 and 4/21.

Although the pitch was helpful for spin,[54] a total of 74 overs in the match yielded 3/146, as Johnston was unable rekindle the form of 1948 following his knee injury.

[12] After going wicketless in the opening season's tour match against the Englishmen, Johnston took a total of 7/122 against South Australia and retained his place in the team.

[6][7] He had another notable innings when he joined Neil Harvey with 78 runs needed for victory on a difficult batting surface against the hostile pace of Frank Tyson and Brian Statham.

[11] His teammates Alan Davidson and Peter Burge removed a bench from the dressing room wall and used it as an improvised stretcher to carry Johnston from the ground;[51] his Test career ended without bowling or batting in either of his last two matches.

The late swing in flight which generated the batsman's uncertainty over the direction in which the ball would move was responsible for the majority of Johnston's wickets in England.

[39] According to teammate Alan Walker, Johnston bowled at least as many bouncers as his colleagues, but because of his happy nature, observers thought that he eschewed the short ball.

During his early first-class career, upon returning from matches, he would read articles by Bradman, Bert Oldfield and Arthur Mailey from a book given to him by his schoolteacher when he was a schoolboy.

[8] In the last match against T. N. Pearce's XI at Scarborough, English Test paceman Alec Bedser bowled wide of the stumps and advised Johnston not to do anything that would lose him his wicket.

David played 10 matches for South Australia at first-class level;[3] He later became an administrator and was the Chief Executive of the Tasmanian Cricket Association at the time of his father's death.