The court also convicted 11 other accused in the case for which the sentence will be pronounced on August 27.
One of the accused, Bala Surve, died during the trial, while three accused were acquitted for lack of evidence.
Jamsandekar was shot dead in March 2008 at his Asalpha residence in suburban Ghatkopar. Gawli was arrested on May 21, 2008, and has been in custody since then.
On October 7, 2010, the court had framed charges against Gawli and other accused under MCOCA, sections 302 (Murder), 34 (common intention) and 120B (criminal conspiracy) of the IPC, while Gawli and others had pleaded innocence in the case.
According to the police, the contract for the killing Jamsandekar was allegedly given by accused Sahebrao Bhintade and Bala Surve, who were reportedly his (Jamsandekar's) rivals in the construction business and local politics.
The crime branch had said the other reason why Jamsandekar was executed was that Bintade and Surve were eyeing a plot at Saki Naka in suburban Mumbai and Jamsandekar reportedly "refused to cooperate".
According to the prosecution, Jamsandekar was murdered at the behest of Gawli, who had, along with the co-accused, conspired to execute him.
The chargesheet said that a sum of Rs 30 lakh was paid to the Gawli gang for the job. The trial had commenced from October 2010.