He is the older brother of P. Waytha Moorthy, HINDRAF (the Hindu Rights Action Force) lawyer who headed a team of lawyers to file a class action suit against the United Kingdom for "abandoning minority Indians to the mercy of majoritarian Malay rule while granting independence on August 31, 1957".
He also wore a pin of the Malaysian flag on his blazer during his student times, despite the fact that his friends poked fun at him.
On 30 October 2007, Uthayakumar and other HINDRAF lawyers – M. Manoharan, P. Waytha Moorthy and V. Ganapathi Rao were arrested at 11:00 p. m. and detained until 8:00 a. m. the following morning for taking part in a demonstration against the demolishment of a Hindu Shrine in Kuala Lumpur.
[5][6] On 19 November 2007, Uthayakumar's office in Kuala Lumpur was raided by the police to search for a book deemed seditious under the Sedition Act.
In his police report, Uthayakumar stated that he suspects the United Malays National Organisation (UMNO) to be behind the slashing.
He also stated that a car bearing licence plate number AFL5280 was spying on him for the past eight months and that should anything happen to him, he would hold UMNO's top leadership responsible.
[9] On 13 December 2007, Uthayakumar and other HINDRAF members M. Manoharan, V. S. Ganapathy Rao, K. Kengadhadran and T. Vasantha Kumar were arrested under the Internal Security Act (ISA).