In 2000, he starred in Super Good Films, Maayi and made a guest appearance in Pennin Manathai Thottu. Despite facing controversy, Maayi proved to be successful at the box office with a reviewer citing that "In the title role of a totally underplayed character, Sarathkumar surely makes a mark". In the start of 2001, he acted in the action film Rishi and went on to appear as himself in Ullam Kollai Poguthae, both directed by Sundar C. He co-starred with Vikram in Vinnukum Mannukum, directed by Rajakumaran and produced by R. B. Choudary. The film, released after many troubles and eventually failed at the box office. He then acted in S. A. Chandrasekhar's Dosth. His next release was K. S. Ravikumar's family drama Samudhiram; he acted alongside Murali and Manoj Bharathiraja. Despite negative reviews, the film was a commercial success. The next year, he appeared in Thenkasi Pattanam, alongside Napoleon and Samasthanam, alongside Malayalam actor Suresh Gopi, both were two hero-subjects. Sarathkumar's first 2003 release was Arasu, directed by Suresh, and the film was successful at the box office. However, his second film Paarai, a remake of the Malayalam film Mahayanam, directed by K. S. Ravikumar was an average grosser. His third film was Diwan, directed by Suryaprakash, who previously directed the successful Maayi. His performance was praised by critics. In the start of 2004, he acted in the action films Chatrapathy and Gambeeram; both were average grosser. In the making for the last five years, Maanasthan was released to average reviews. His next venture Aai, in which he co-starred with Namitha and Vadivelu, an action masala film, directed by A. Venkatesh, was a decent hit. He was also introduced as a playback singer in Aai.
In the mid-1990s, Sarathkumar was involved in a relationship with actress Nagma, with whom he paired in films such as Ragasiya Police, Aravindhan and Janakiraman. After knowing of their relationship, Chaya filed a divorce petition. Sarathkumar and Chaya got divorced in 2000.