Maheshwari, representing Tamil Nadu, had a leapt of 16.85m in his fifth and penultimate attempt which was the exact distance for 'B' qualification standard for London Olympics.
Young Arpinder Singh of ONGC was a distant second in 16.20m while the bronze was won by Raja Sekar of Tamil Nadu with a leapt of 15.79m.
Maheshwari, a former Asian champion and bronze medallist at the Delhi Commonwealth Games, started with a moderate 15.84m and went on to improve it with 16.51 and 16.56 in his next two rounds before making a foul jump on the fourth. His fifth attempt saw him achieve London qualification 'B' standard and he had a no mark in his final round.
He also erased the old meet record of 16.72m which he himself created in 2007. It was Maheshwari's third win in the Federation Cup. He had earlier won the titles in 2005 and 2007.
In other events, Maharashtra sprinter Krishna Kumar Rane (10.51 secs) pipped defending champion Shameer Mon (10.54) of Kerala to become the fastest man of the meet. Manikananad Raj of Andhra Pradesh with third in 10.55s.
Haryana's Manisa, winner of the previous edition in 2010 in Ranchi, successfully defended her title in 11.93s. Srabani Nanda (12.06s) of Orissa and Shirke Bhagyashree (12.28s) of Maharashtra were second and third respectively.
Javelin thrower Suman Devi proved her mettle once again with her sixth win in this championships.