This founder used to split his time between Amazon and the army, and it shows

Isaac Oates manages a team of 42 people at Justworks, an HR and payroll management startup that he founded in 2012.

Justworks wants to take the pain out of starting a business by making it easy to get employees enrolled in a benefits plan.

Oates is pretty familiar with operations: He spent 12 years in the Army Reserve, enlisting with the help of a parent's note at the ripe young age of 17.

"The army has a certain style of leadership that people find attractive," Oates said. "Anyone who knows me well knows that I like doing things in a very clear, specific way. Also, treating people like family is important to me."

He did ROTC during college and became an officer upon graduation.

He soon got a full-time software engineering job at Amazon, but he continued to take weekend shifts with the National Guard and Army Reserve. He also worked on counterterrorism analysis and commanded his own team.

"It kind of became a hobby while I was working full-time," Oates told Business Insider. "Those are really useful skills for any job."

He ended up having two separate stints at Amazon between 2002 and 2009: nearly three years as a software engineer, then, after a short break for business school, a year and a half as a product manager. He worked with the National Guard for that entire stretch of time, though he did have to take a six month-leave from Amazon during officer training.

Amazon had a similar focus and rigor to the army. Oates described the Amazon experience in a blog post that was shared widely earlier this year:

When you go to a meeting with Jeff Bezos at Amazon, you spend time preparing a document. It could be called a narrative, a 1-pager, or something else - the name doesn't really matter. The document is an articulation of what you are trying to accomplish and your understanding of what it will take to get there. The document is long, thorough, and written in prose.

When you present to Jeff for an hour, you spend the first 20 minutes while he reads your narrative, making notes in the margins. Everyone else waits. It sounds like a waste of time, except that the following 40 minutes is pure gold. For 40 minutes, you have a strategic discussion where everyone in the room is on the same page, has the same context and access to detail.

I believe that those meetings, along with Jeff's intellect, are Amazon's true competitive advantage. They think better than their competition. Great decision-making and execution follow.

Into the startup world

Oates left Amazon in 2008 and started his own company, an ad platform called Adtuitive. The five-person startup was acquired by Etsy in 2009.

The difficult experience of getting Adtuitive off the ground would serve as inspiration for Oates' current project: Justworks.

"When we were trying to set up health care for our employees, we found that it was really complicated, and all of the forms and laws for benefits were different in other states," Oates said. "We just kept thinking, 'How do we make this better?'"

To set up benefits through Justworks, a business owner only needs to set up an account and invite employees to the system. Employees then choose from various benefits packages. Everything from medical insurance and payroll to commuter benefits and 401(k) accounts can be managed through Justworks. Casper, Trello, and Ringly are among the startups who have signed on to use the service.

"The product definitely appeals to companies that are run by younger people," Oates said. "We also work with lots of agencies and creative people, as well as some doctors and dentists."

Oates' experiences definitely influence how he runs Justworks today. As he wrote about his time at Amazon:

To this day, I avoid laptops in meetings and encourage presenters to participate as best they can. It's tough. There's a lot of pressure to be online and available all the time, much more so even than in 2009. I'm hopeful that by creating a place where distractions like email, social media, and Google can be avoided, I can get my team's best thinking.

Justworks has raised $20 million in venture funding to date. Their most recent round was a $13 million Series B led by Bain Capital Ventures. Earlier investors Thrive Capital and Index Ventures also contributed to the round.

Disclosure: Jeff Bezos is an investor in Business Insider through his personal investment company Bezos Expeditions.