Born Sonia Walia on 19 February, 1964, she was a Psychology graduate and student of journalism before she took up print and ramp modeling. Participating in the Miss India contest in 1985, Sonu Walia won the pageant and took over the crown from Miss India 1984 – Juhi Chawla. She also represented India in the Miss Universe 1985 competition.
A popular face, Sonu entered films, featuring in Shart (1986). She played a model in this crime thriller, revolving around a series of brutal murders. Two years later, she had two releases—Akarshan (1988) and Khoon Bhari Maang (1988). Akarshan was directed by Tanvir Ahmed and produced by Pramod Kumar Saraswat. Besides Sonu Walia, it starred Akbar Khan, Sharon Prabhakar, Rohini Hattangadi, and Girish Karnad. The film revolved around Priya (Sonu Walia), an actress whose life is saved by Abhishek, the actor playing the hero, while shooting.
The blockbusting Khoon Bhari Maang (1988) was the film that got Sonu Walia noticed and appreciated. As a rule, filmmaker Rakesh Roshan does not work with newcomers; however, with the Miss India title under her belt, Sonu managed to bag the film, helped by the fact that she had also featured in Akarshan. Her performance in Rakesh Roshan’s revenge saga, Khoon Bhari Maang which released the same year as her debut film, grabbed eyeballs, as she played the model Nandini with negative shades. The film told the story about a man who marries a rich widow for her money and tries to murder her; however, she survives, gets a new face thanks to plastic surgery and returns for revenge. Sonu Walia won the Filmfare Best Supporting Actress Award for her performance in this Rekha-Kabir Bedi-starrer.
Sonu was, however, largely typecast as a glamorous woman in the films she was offered, in the course of her career. She featured in films such as Clerk (1989), Apna Desh Paraye Log (1989), Tejaa (1990), Maha-Sangram (1990), Khel (1991), Dil Aashna Hain (1992), Tahalka (1992), Sahibaan (1993), Fauji (1995), Yash (1996), Kasam (2001), Suryakaant (2005), and Jai Maa Sherawaali (2008).
She also enjoyed a successful stint in television. She played a TV reporter in the serial Betaal Pachisi, a 49-episode Hindi series which originally ran from 1997 to 1998 on DD National. Based on the comic series, The Phantom, it was directed by Sunil Agnihotri, and starred Shahbaz Khan, Sonu Walia, Puneet Issar, Tom Alter and Vindu Dara Singh. Sonu also acted in the serial Detective Karan, and in Mahabharat Katha, in which she played the role of Maharani Chitrangadhaa, mother of Babruvahana.
She also turned producer with Jogiyaa Rocks (2016). Directed by Mahesh Nair and Vineet Sharma, its star cast includes Kirti Kulhari, Rohit Bakshi, Abhijit Sinha and Suzzana Mukherjee.
On the personal front, Sonu Walia was married to Surya Prakash, an NRI hotelier and film producer based in the USA. He passed away in 2009.