Hundreds of DMK workers, most of them wearing white shirts, cheered as Ms Kanimozhi, 49, emerged from the airport, hands folded and a smile on her face.
Mr Raja and Ms Kanimozhi then headed straight to DMK chief Karunanidhi's residence to meet him, where dozens of excited party workers were again waiting in a show of strength.
The two DMK leaders were among the 17 who were acquitted on Thursday of corruption and money-laundering when mobile network licences were issued in 2008. A special court in Delhi said the CBI failed to provide any evidence of a conspiracy among politicians, bureaucrats and top corporate executives.
The telecom scandal, named the 2G scam after the second-generation airwaves involved, played a large role in the perception of Dr Manmohan Singh's government as seeped in corruption. The DMK was a key member of the Congress-led national coalition. They also contested last year's election in Tamil Nadu together, only to be emphatically defeated by J Jayalalithaa and her AIADMK.
Ms Kanimozhi, Mr Karunanidhi's daughter and a two-time MP, was also accused of corruption in the case and was in jail for seven months. Seen as the literary heir of Karunanidhi, the 2G allegations and the jail term meant she was only given a marginal role in the DMK, while MK Stalin established himself as working president with their father's health deteriorating.
Her supporters now hope Ms Kanimozhi will be suitably elevated in the party.