Jonathan Millmow was selected for the 1990 tour of England after several seasons of developing promise on the New Zealand domestic scene. He was a key part of the Wellington side which was to the forefront of both the first-class and one-day programmes in New Zealand during the late-1980s. His rise to international status began after a tour to Zimbabwe in 1988 with the New Zealand Young Internationals side. In the 1989-90 season, Millmow finished second on the New Zealand bowling averages, taking 33 wickets at 21.18, to help Wellington win the Shell Trophy.

A fast-medium bowler, he used his height to good advantage to gain steepling bounce on harder pitches which complemented his natural outswinger. This was especially the case in the match against Otago on a faster Basin Reserve pitch in Wellington. He took his career best figures of 6 for 13 in the first innings when Otago were dismissed for 57, and followed that with 4 for 70 as Wellington took an eight-wicket win. He was seen as a player capable of filling the mantle soon to be left vacant with the pending retirement of Richard Hadlee. However, halfway through the tour of England, shin splints forced Millmow out of the tour which had started with a tournament in Sharjah. He played five one-day internationals.

Back in New Zealand, Millmow battled hard to recover his best touches and in the summer of 1991-92, he offered an early suggestion that he was back on track when taking 5 for 49 and 3 for 44 for Wellington against Auckland. But, in the following game against Central Districts, he broke down in the first innings of the game, and he didn't recover. While he continued to try to come back, his career was complete, left on a statistical frustration of 99 first-class wickets at 28.19. While disappointing for him, it was also reflective of the disappointment felt by a cricket public robbed of a player who had offered the prospect of penetration, at a time when there were few assets available. Millmow entered a career in journalism and became the cricket writer for the Dominion Post newspaper in Wellington.
Lynn McConnell