A Tribute to a USMC Legend - Sean Leahy

We lost a great warrior and legend from the USMC infantry officer community a few weeks ago - Sean Leahy.

I hope this tribute does justice to his memory.

The first time I met Sean, he scared the sh*t out of me ??

Before I jump in, the goal of this post is to tell a story and encourage you to donate to this gofundme -

Let's get into it -

The Infantry Officers' Course (IOC)

My class was waiting to start the infantry officers' course (IOC) - a notoriously challenging rite of passage for USMC infantry officers.

We were learning to fast-rope out of helicopters and were terrified to make a mistake for two reasons -

1. Falling from the sky and breaking your legs

2. The 6'4" 260 lb Irishman named Sean Leahy standing by the side of the tower

I was moderately nervous about falling but truly terrified of Sean kicking my ass if I let go of the rope.

I held onto the rope and moved on to IOC.

IOC is the course molds 22-year-old bright-eyed and bushy-tailed lieutenants into leaders who are prepared to lead in chaotic and violent situations.

The Marine Corps infantry is sent into combat - that's what we do.

The instructors' job at IOC was to transform us from kids who believed that there is value in "giving it your best" into warriors who know that the only thing that matters is victory in combat.

No trade secrets here, but the course contains a fair bit of fighting to help indoctrinate young men into a culture of violence.

Violence is taboo in American culture, but it becomes the center of your world during the course.

This brings us to Sean.

It's impossible to write about Sean without acknowledging that he was the most physically intimidating man I have ever met.

At 6'4", 260 lbs, Sean was massive.

Last year, 10 years AFTER I met him in IOC and after Sean left the corps, he entered a Muay Thai competition.

He set a kickboxing / Muay Thai record when he KO'd someone in 13 FREAKING SECONDS.

Not a bright move to jump into the ring with Sean - even at 41 years old, he was a legend.

Watch the first 60 seconds of this clip and you'll get what I'm talking about, he was huge -

So when I met him in his prime at IOC, fear was the correct response to his presence.

Sean was a Leader, Mentor, and Teacher

In addition to being the most physically intimidating man I have ever met, Sean was a brilliant infantry officer.

Sean could take a concept and break it down so simply that you could start to understand it intuitively.

He demonstrated how to simplify concepts, and how to teach them to others - a critical skillset for an infantry officer.

The instructors at IOC are among the best and brightest that the Corps has to offer - they are selected from among their peers to train the next generation. Sean was a leader among these all-stars.

He trained infantry officers and left a mark on every Lieutenant who came through IOC from 2010 - 2012.

Graduating from IOC remains one of the highlights of my life. This is because men like Sean Leahy made me earn it.

Thankfully, IOC graduation was not the last time I saw Sean.

A Leader Through My Transition

When I got back from Iraq in December of 2016, I moved to Advisor Training Branch (ATB) for the remainder of my time in the Marines.

After a brief vacation in the summer of 2017, I returned to work to find that Sean Leahy was my new boss.

I had no idea what to expect from him.

Our unit, ATB, trained advisors who were headed to Iraq and Afghanistan.

The Marine Corps loves to throw around terms like "tip of the spear" to convey that we're the first people the country sends into combat.

In reality, most units are somewhere along the shaft of the spear - obviously important, but certainly not the business end.

Our unit was more like the butt of the spear - the part you drive into the ground when you're taking a break so that it stands upright.

Our tiny org was poorly resourced - we got Marines who were in their last 6-12 months in uniform. This was true for Sean and I as well - we were on our way out.

This was when I saw Sean's true colors - the man simply had no quit in his body. He dedicated himself to leading his Marines and providing world-class service to the Marines we trained for overseas.

Sean went to Iraq to visit deployed Marines so that he could shape the training we provided. He didn't have to, but couldn't imagine living any other way.

He empowered and inspired me to make a difference during my last year in the Marines - giving me more than enough rope to become a better operator, planner, organizer - skills that have served me well in my civilian life.

He gave me direction and provided top-cover when I inevitably screwed up.

Life After the Corps

I met up with Sean when we had both transitioned out of the Marines in Philly.

I was about to start at Wharton, and Sean had taken a job at a chemical plant outside of the city.

He was full of life - he had time to dedicate to his boys who were the center of his world.

Over the ensuing years, we chatted a few times on the phone - he took it upon himself to check in on me, and he encouraged me to continue fighting through the startup grind.

I'm really at a loss for how to conclude this post - Sean was a mentor of mine and later a friend. He passed on December 2nd, 2022.

Here are the takeaways I learned from Sean -

1. A leader gives to his community and tribe.
2. Overcoming fear is like being punched in the face - it's never as bad as we imagine.
3. Stay physically strong and mentally tough.
4. See things through - especially in challenging times.

If there is a Valhalla, I have no doubt that Sean is waiting there to ground fight every person who thinks they deserve a spot.

If you're in the giving mood this holiday season, I would encourage you to donate to his family's gofundme here -

Leave your favorite memories of Sean in the comments below.