Her Sindhi father, Ashok Idnani, is a businessman and voice modulation trainer and her Gujarati mother, Falguni Dave, is a television actor.

[4] Siddhi Idnani started her career as a theatre artist known for the Gujarati commercial play Aaje Ravivaar Chec.

She is well known for her role in the Tamil film Vendhu Thanindhathu Kaadu directed by Gautham Vasudev Menon and starring Silambarasan.

[5][6] Her upcoming films include Nooru Kodi Vaanavil with critically acclaimed director, Sasi.

In 2023, Idnani starred in The Kerala Story, in which she played the role of Geethanjali Menon / Anisha Ba, who goes through struggles of societal identities and beliefs and converted to Islam, while realising the situation and eventually returning to her family but gets trapped in complexities.