Gil was raised in Ramat Gan, he joined the Israel Air Force from where he retired at the age of 22. He emigrated to USA. There in partnership with Erez Ram, also a veteran of the Israeli Defence Forces, he founded in 1992, American Hi Definition Inc, a company involved in high definition big screen video projection. In 1997 with Erez Ram and Joe Shckelford they started another company, Sweetwater Digital. In November 2010, the companies were acquired by NEP Broadcasting.
After this sale Gil became a full-time animal rights activist. He donated US$6 million to his organization Ady Gil World Conservation. Gil set up a shelter for cats and dogs in Los Angeles and paid for sterilization of 6000 cats in Israel. He built a large roosting structure for eagles in a wildlife sanctuary on Mount Carmel. Gil donated millions to Sea Shepherd Conservation Society to refurbish a ship for use for its anti-whaling campaigns, the ship was given his name Ady Gil, the ship suffered sinking 290 km from Antarctica as a result of an incident with the Japanese ship Shonan Maru No 2 used for killing whales. The loss of the ship has been the subject of litigation between Gil and Paul Watson founder and director of Sea Shepherd Conservation Society. In December 2014, Gil paid US$2 million to rescue 1300 monkeys from a facility that bred them so that they would not be exported to the United States for being subjected to experiments that maimed and killed them.
- Shuan, Amir (2014-12-23). "Israeli buys 1,250 monkeys, saving them from harsh fate". ynetnews.com. Retrieved 11 February 2015.
- Kurz, Phil (2010-10-15). "NEP Broadcasting adds Sweetwater, American Hi Definition". tvtechnology.com. Archived from the original on 11 February 2015. Retrieved 11 February 2015.
- "Ady Gil and Japanese whaler both blamed for collision". The Guardian. 2010-11-18. Retrieved 11 February 2015.
- Choe, Kim (2013-01-10). "Ady Gil sues Sea Shepherd over Antarctic sinking". www.3news.co.nz. 3 News. Archived from the original on 11 February 2015. Retrieved 11 February 2015.