Horseman was a book illustrator, fashion artist and comic book artist who worked on the 1950s comic strips, 'Pam' and 'The Clothes Horse'.

Horseman's parents separated when she was 13 and she went with her mother to England and then Germany. When she returned to Australia she was briefly employed by Norman Lindsay and his wife as a governess for their two daughters. Lindsay was impressed with her drawing skills and recommended she study art. She did part of a course at East Sydney Technical College.

In 1929 Horseman and Joan Morrison became the first female cartoonists to be permanent employees at Smith's Weekly. She was married and divorced twice in the thirties before moving to Brisbane in the early forties, where she freelanced, drawing comics for Frank Johnson Publications and cartoons for Man magazine, Australian Woman's Mirror and Rydge's Business Journal, where she created 'The Tipple Twins'.

From 1946 she worked in production at the The Courier-Mail before taking over Jean Cullen's comic strip 'Pam' for the Sunday Mail and 'The Clothes Horse' in The Sydney Morning Herald.

From 1957 to 1967 Horseman lived in Sydney. During the early sixties, she was the staff artist at Everybody's. Her illustrations (anonymous or signed 'Vanessa') included a full-page colour 'Sexy Man' cartoon and the serial 'Girl Crusoe' (1964).

Between 1967 and 1969 she returned to Brisbane and illustrated books for Jacaranda Press. She then moved to the Blue Mountains in NSW while freelancing and painting landscapes. Her right hand was paralysed after being hit by a car in 1973 and she taught herself to draw with her left hand.