"Consumer spending is 70 percent of economic activity in the United States," Reich said. "We depend on consumer demand and yet consumers are running out of money. The new jobs that have been created since the recession pay on average less than the jobs that were lost. As the median household keeps on having less and less income, there is a very profound and important question about where demand is going to come from in our nation."
(Watch: U.S. consumers out of purchasing power?)
A former secretary of labor in the Clinton administration and now professor of public policy at the University of California, Berkeley, Reich has been criticized by some conservatives for promoting economic policies seeking redistribution. Striking a bipartisan tone, Reich said his push for income equality is "not a matter of fairness."
"The purpose of this movie, honestly, is to say regardless of your political ideology or party, you have got to understand the problem," Reich said. "This is not about blame. Stop blaming the poor or the rich or the government or big business or Wall Street. Understand the forces that are at work here. Understand this is very big."
"Inequality for All" director Jacob Kornbluth states on the documentary's website that the film was designed to transform a conceptual issue into a story that average humans can understand.
"Income inequality is eroding everybody's standard of living eventually, even the very wealthy," Reich said. "It's causing huge divisiveness in our country. It's undermining our democracy. The United States actually has a more unequal distribution of income than any other advanced country."
Drawing on his days in the White House, Reich acknowledged Washington's "deadlock," saying there is "no chance" Congress can pass any economic policies correlated with the widening income gap. Among possible policy changes, Reich promotes investments in education and infrastructure and restructuring financial and tax regulations.
(Read more: Washington likely to drive Wall Street)
"There's not one individual solution, but if we don't get together, roll up our sleeves, stop bickering and do something about this, our economy is going to suffer," Reich added.
"Inequality for All" debuts in theaters Friday.