In theater, Decleir played with the Blue Monday Company, the Toneelhuis and Theater Antigone in, among others, En deliver us from evil, In the name of the Father and the Son, Ten war and Nachtlied and directed, among others, Overleie, The Best of Shakespeare, Just of Faust and the Lice Opera.

In 2007, she founded Tutti Fratelli, a theater company for people who have fewer opportunities in society.

Decleir appeared in a number of Flemish films and TV series.

In 2009, she had the lead role as Maria 'moemoe' Vangenechten in the television series Van Vlees en Bloed.

[1] Decleir died at the age of 73 as a result of euthanasia; at the time of her death, she had cancer.