These 16- to 18-year-olds were disproportionately male and Hispanic, and ended their education either at the beginning of high school or nearing the end.
Roughly 75 per cent of them are native-born Americans, the new study said.
Granted, high school graduation rates among Hispanic students have climbed in recent years, with 75 per cent receiving a diploma in 2013 compared with 71 per cent two years earlier, according to the latest data from the Education Department.
Still, young Hispanic men are at high risk of leaving school to work, the Urban Institute study found.
The dropouts aren't earning much.
Six out of 10 teenagers identified in the study earned less than $10,000 a year working in restaurants, on construction sites, cleaning buildings, among other things.
A third of the kids contribute more than 20 per cent of the total annual income of their households, one-tenth contributed more than 50 per cent, the study said.
On average, what these teenagers earned made up almost a quarter of the money their families needed to live.
And that money kept 42 per cent of households from falling below the poverty line.
Given that wages are stagnant and many high-paying blue collar jobs are disappearing, more low-income families may simply need more workers in their households to stay afloat, the study concluded.
The research fits into a larger conversation about education and income inequality.
There has been a lot of discussion about college affordability and access being critical in providing students a path out of poverty.
But there is also a pressing need for policy solutions to reach teens who may be at risk of trading off their high school education to support their family.
"We have a lot of assumptions about dropouts being checked out," said Molly Scott, one of the authors of the report and a senior research associate at Urban Institute.
"But when you look at the amount these kids are working and contributing to their households, they have a lot of economic responsibility at a young age."
As a result, the prevention strategies commonly used to help at-risk youth, such as early academic and behavioural intervention, just aren't enough to help these teens, according to the researchers.
With that in mind, any intervention for children who play an economic role in their household may have to help them and their families, based on the study.
Researchers suggested policymakers consider providing parents training, job placement or access to resources that could ease some of the economic stress.
Many of the teenagers identified in the study lived in households that didn't take advantage of safety-net programs such as food stamps or cash assistance.
Policymakers also need to support youth employment programs that pay market wages, which many summer job initiatives don't, Scott said.
Considering that students are at risk of leaving school to help meet their families short-term economic needs, higher wages in these programs could alleviate some of the pressure.
"The elephant in the room in conversations about dropouts and even in higher education is poverty," said Scott, noting that 65 per cent of those who quit high school are at or below the poverty line.
"If there is an economic element to the reasons why folks drop out or don't continue their education, then our interventions need to treat it like that."
