The firm plans to split into a "New GM" made of its best assets and an "Old GM" that will be liquidated under court protection.
The reorganisation of GM will be financed by $30.1bn from the US government - on top of the $20bn it has already handed the company - giving it a 60 per cent equity stake in the car firm.
Young said the firm is expected to remain a private company at least until early 2010.
GM did not name the proposed buyer of its Hummer brand or the price, but said the sale could save more than 3,000 US jobs in manufacturing, engineering and at various Hummer dealerships.
The firm bought the Hummer brand from AM General in 1999 as it soared in popularity. However, sales collapsed as oil prices rose.
GM's deal to sell the brand includes plans by the unnamed investor to aggressively fund future Hummer products, it said.
Young also said GM had received interest from 16 parties for its Saturn brand and is in discussions with three parties regarding the sale of its Saab Swedish brand as part of efforts to slim down the company.
Monday's bankruptcy filing capped a three-decade-long decline for the Detroit car- maker.
Founded in 1908, GM rose to dominate the US and global car industries under the stewardship of Alfred Sloan, its then chief executive, who famously pledged the firm would deliver "a car for every purse and purpose".
By the mid-1950s, at the peak of its success, GM had about 514,000 employees and it accounted for about half of US new car production.
But in recent years, GM and the US car industry in general has been hit hard by a slump in sales amid a recession in the US and the global financial crisis, cutting thousands of jobs and closing plants and dealerships.