Grimshaw's career began in 1981 when she joined
Nine News in
Melbourne as a reporter. In 1985 she began presenting news bulletins and by 1987 had been appointed the presenter of
Nine Morning News. Through the early 1990s, Grimshaw reported on overseas events for the
Nine Network, as well as reporting for
A Current Affair and hosting the program over the summer non-ratings period. In 1995, Grimshaw appeared as co-host of
The Midday Show with
David Reyne. The following year she was host of
Today on Saturday and
Animal Hospital. On 30 January 2006, Grimshaw began presenting
A Current Affair, replacing
Ray Martin. In May 2006, she interviewed
Beaconsfield Mine collapse survivors Todd Russell and Brant Webb in a special two-hour presentation called
The Great Escape. The Nine Network announced in September 2023 that Grimshaw would be returning to the network in 2024. On 19 January 2024, at a Nine media event in
Melbourne, she was announced as the host of a new medical series,
Do You Want to Live Forever?, alongside medical expert
Nick Coatsworth, ==Personal life==