Sneha, born as Suhasini, is the daughter of Rajaram Naidu and Padmavathy, a Telugu family as youngest of the 4 children. She was born in Mumbai and her family immediately moved to Sharjah, Dubai where she completed her studies. The family later settled in Panruti, Tamil Nadu where she owns a Marriage Hall.
Fazil recommended Sneha to Anil-Babu who was searching for a heroine for his love story Ingane Oru Nilapakshi (2001). The film featured Sneha as an aspiring dancer, with the actress performing for seven classical songs. She was signed by Susi Ganeshan for his directorial debut Virumbugiren in 2000, which however became long delayed and Ennavale opposite Madhavan became her first Tamil release. The film proved to be a commercial failure. Later that year, Sneha starred in N. Linguswamy's family drama Aanandham, which featured her as part of an ensemble cast and in K. Balachandar's Parthale Paravasam. She finished the year with a foray into Telugu cinema, with an appearance in Priyamaina Neeku, followed by Tholi Valapu. Sneha was part of a total eight films that releases in 2002. M. Raja's Hanuman Junction became a major success. Other films that year included the Vasanth's Hey! Nee Romba Azhaga Irukke, Unnai Ninaithu and April Madhathil. The former bombed at the box office, while the latter emerged commercially successful. Her performance in Unnai Ninaithu led to her being awarded the first Filmfare Award for Best Supporting Actress. Subsequently she acted in lead role in King and a supporting role in Pammal K. Sambandam with Vikram and Abbas, respectively. Virumbugiren that featured Sneha as a rustic village belle, eventually released in December 2002 and went on to win several Tamil Nadu State Film Awards; Sneha herself won the Best Actress award.
Sneha acted in two films in 2003, Vaseegara with Vijay and a heroine-oriented double role in Parthiban Kanavu. While the former was a failure, the later was a huge success. She received high praise for her performance in Parthiban Kanavu, with The Hindu writing: "Till date this is the best role that has come Sneha's way and the charming actress has utilised the opportunity well. With make-up or without it, Sneha sparkles". 2004 was a mixed year for the actress, with Jana, Bose and Adhu all failing at the box-office. However, Vasool Raja MBBS opposite Kamal Haasan and Autograph and the Telugu film Venky were huge successes.
The years 2005 and 2006 saw her acting in Telugu films such as Sankranthi with Venkatesh, Radha Gopalam with Srikanth, Sri Ramadasu with Nagarjuna, and Thuruppu Gulan with Mammootty winning plaudits at box office, while others released in the respective years turning as average grossers at the box office. She essayed the role of a commercial sex worker in Selvaraghavan's Pudhupettai, starring Dhanush. With Thuruppu Gulan, she paired with Mammootty. In the year 2006, she made her debut into Kannada film industry through Ravi Shastri, which remains her only Kannada project till date. In 2007, Sneha starred in Naan Avanillai a super hit and first hit since 2004, while her Telugu films Madhumasamand Maharadhi and Tamil film Pallikoodam turned out to be above-average grosser at box office. Pirivom Santhippom, which saw her collaborating with Karu Pazhaniappan again, was her first film in 2008. Co-starring Cheran, the film opened to critical acclaim and emerged a sleeper hit, while fetching Sneha plaudits and several accolades. A review from Sify noted that she was "superb as Sala a woman torn by the dualities of her existence", labelling it as her "career best performance". She won her second Tamil Nadu State Film Award for Best Actress, besides the Vijay Award for Best Actress and nomination for the Filmfare Award for Best Actress Award. Her Cameo appearance in the film Kuselan with Rajinikanth marked her 50th film in her career. She tried highly glamorous roles with Pandi and Inba, both turning out to be average grossers. She paired with Silambarasan in Silambattam which gave her another commercial success. Her Telugu films Nee Sukhame Ne Korukunna and Pandurangadu turned out to be average grossers while Adivishnu flopped at the box office.
The thriller films Achchamundu Achchamundu, co-starring Prasanna and Hollywood actor John Shea, and Amaravathi, were her only releases of 2009 in Tamil and Telugu, respectively. Both films won many plaudits for dealing with bold themes of pedophiles and womb stealing, respectively. The former film won many awards in the International Panorama and the later grossed average at box office.
In 2010, she starred in Venkat Prabhu's Goa. She again forayed into a glamorous ultra-modern chick role with a few shades of grey. She made cameo appearances in Vishal's Theeratha Vilayattu Pillai and the critically acclaimed Vasanthabalan directorial Angadi Theru. She also appeared in three Malayalam films. She acted in Pramani with Mammootty and paired up with Mohanlal for the first time in Shikkar, The Hunt, which was a huge success and considered as a milestone in Mohanlal's history. Her last release of 2011 was Vande Mataram. Starring opposite Mammootty again, she played an aviator in the film, which released to mixed critical response and bombed at the box-office.
In 2011, she was first seen as a tough Police Officer in Bhavani IPS, which opened to mixed reviews and bombed at the box office, although Sneha received praise for her performance. Ponnar Shankar, a period film penned by M. Karunanidhi, where she appeared as a warrior-princess, opened to mixed reviews and didn't do well at the box-office. Rajanna, a period film based on Telangana issue opposite Nagarjuna for the second time, released on December 22, 2011 to stupendous reviews.
Sneha was to make her Bollywood debut with Mad Dad, alongside Naseeruddin Shah and Ayesha Takia to be directed by Revathy S Varma. Sneha was also roped in to play Sita in Rajkumar Santoshi’s Ramayan featuring Ajay Devgn in lead. However, both the projects failed to take off.
She has appeared in many commercials like Saravana Stores, Horlicks, Roobini Oil, Aashirvadh, Idhayam Dots, Jos Aalukkas, Power Shampoos, Shree Devi Textiles, Preethi Mixi, GRB Udhayam Ghee, Papilon, Vencobb Chicken, Nisha Fairness Cream etc. In 2010, she was announced the brand ambassador for Dabur Amla Nelli Hair Oil and Cavin Kare's Chinni's Pickle.
She also appeared in numerous Fashion Shows like Chennai International Fashion Week, Sydney Sladen Fashion Week and other shows which are held in Chennai and Mumbai.
Sneha was paired with Prasanna for the first time in Achchamundu! Achchamundu! (2009). Since then, there were numerous reports in the media on their affair. Prasanna was spotted in all her modeling shows and both were spotted together in Movie Previews. Though, both declined it as rumour, later, on November 9, 2011 Prasanna announced, "Yes... Sneha and I decided to marry soon with the blessings of our parents. The engagement will be announced later. Someone has mentioned that our marriage would be in March 2012. There is no truth in that report. We have planned to announce our marriage date properly later on. Till then, please wait and thanks for all!" through his PR. Sneha, later acknowledged the same on November 16, 2011.