Kilner first played for Yorkshire as a batsman before the First World War, establishing a regular place in the side. After being wounded in the war, he returned in 1919 to a Yorkshire side which was short of bowlers. As a result, Kilner began to practise his bowling to the point where he became highly regarded as a slow left-arm bowler. His aggressive batting and warm personality made him a popular player with both cricketers and spectators. His form brought selection by England in 1924 and a visit to Australia for the Ashes tour of 1924–25. Although the second most successful bowler of the tour, his bowling subsequently declined in effectiveness, and did not trouble batsmen on good pitches. He was selected during the 1926 Ashes but dropped for the final Test. Kilner went on several coaching trips to India during English winters, and on one of these, in 1928, he contracted an illness; on his return to England, he died aged 37. His funeral was attended by over 100,000 people and there was widespread sadness at his death.