Madeleine Budd, 21, damaged the life-sized statue of the World War Two veteran in Thistley Meadow in Hatton on 30 September by pouring faeces over the memorial.
Budd, of Kedleston Avenue in Manchester, pleaded guilty to causing £200 worth of criminal damage after appearing at Westminster Magistrates Court on October 4.
She has spent the last three weeks in prison.
A video posted online showed the climate protester pouring human faeces onto the life-sized statue of the Second World War veteran.
She was spared an immediate jail sentence when District Judge Louisa Cieciora handed her a 21-week prison term, suspended for 18 months.
“You had clearly thought about what would cause the most amount of outrage and publicity,” she told Budd, from Kington, Herefordshire.
“The cost of repair was low, around £200.
“Although the substance you used was deliberately chosen as being the most demeaning and disgraceful as possible, equally it was a substance which can be easily cleaned.”
The judge noted her young age and her deeply held views on climate change, adding: “Given your actions could not or have not achieved what you wanted them to and you want to find a better way to express your message… I am just about persuaded I can suspend your sentence.”
Katie McFadden, defending the former Manchester University medical student, said: “She has expressed she will not undertake actions such as this in the future."
“She has clearly reflected on the impact of her actions and expressed how she is sorry for any offence caused to the family of Captain Tom.”
The war memorial was gifted to Thistley Meadow by the managing director of AGC Fabrications, Austin Cox, after the veteran shot to fame during the coronavirus pandemic in 2020.
Sir Tom raised almost £33 million for NHS charities during the summer by walking laps of his garden in the run-up to his 100th birthday.
The 100-year-old was later knighted by the late Queen Elizabeth II before he died of Covid-19 in February 2021.