Before founding TallMark, I spent over 25 years leading teams and partnering with leaders across fast-growth startups and large enterprises. Here’s what colleagues and clients from those journeys have said about the impact of our work together*.
*Testimonials reflect personal experiences and opinions of the individuals and do not represent endorsements by their employers or companies
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“Nathan is the best leader I’ve ever worked for—not just a manager, but a true go-to-market strategist. I’ve seen firsthand how data-driven and thoughtful he is when building territory plans, hiring strategies, compensation structures, and cultures that drive high performance. He has a rare ability to unlock sales leaders and reps by removing barriers and equipping them with what they need to succeed. I owe much of my career growth to his leadership and the pillars he helped instill.”
Sam Turin
Sales Manager, Atlassian -
“Nathan has an exceptional ability to diagnose what’s missing in a business strategy and build a clear, actionable plan to fix it. At Convoy, he helped us rethink how we built the Commercial business—shaping our customer acquisition strategy, aligning cross-functional teams, and driving measurable growth.
Nathan sets vision, defines smart strategies, and enables people to succeed. He doesn’t just build plans—he builds belief. His partnership pushed me to think bigger, lead more confidently, and collaborate more effectively. His support made a lasting impact on how I show up in my work.”
Victoria Kiss
COO, CloudPaper -
“Transitioning out of the military, I wasn’t the obvious choice for a sales role—but Nathan recognized my strengths and understood what I could contribute to a team and client engagements. He coached with purpose and precision, helping me build the skills and confidence to succeed. His leadership was an accelerant in my journey—from a new AE to a confident, effective manager.
For any company looking to hire, develop, or elevate talent from non-traditional paths, Nathan brings the clarity, conviction, and belief that unlock growth.”
Russell Bowers
Sales Manager, Smartsheet -
"Nathan is a master at building sales and go-to-market teams, and driving the right levels of focus and collaboration to enable his teams to do their best work. At Convoy, he built territory and compensation plans that aligned the sales team's focus with the company's strategic objectives, and his teams were known for executing and having fun while doing it.
If your business needs help designing a sales model that drives results, Nathan brings the experience and energy to make it happen."
Brooks McMahon
VP, Emerging Markets & BD
Uber Freight -
“I’ve had the opportunity to work with Nathan at three different companies—and each time, his impact on our go-to-market strategy was transformational. He brings a rare ability to think holistically—from lead generation to closing to retention—and align the entire revenue motion around clarity, accountability, and results.
What sets Nathan apart is that he doesn’t just design the strategy—he builds it. He rolls up his sleeves to put the systems, processes, and people in place to make it real. Whether it's structuring a demand gen engine, creating compensation plans, or developing frontline leaders, Nathan helps companies scale with purpose.
If your business needs help building or refining its go-to-market strategy, Nathan will bring the clarity and execution to drive meaningful growth.”
Alex Gamoran
RVP of Commercial Growth, Smartsheet -
“I met Nathan early in my career during my first role at a scaling SaaS company. He was a business partner who quickly became a trusted mentor and coach—and he’s remained an advisor and friend for over a decade.
Nathan is one of the most genuine and straightforward leaders I’ve worked with. He offers honest, meaningful feedback with empathy and awareness, delivering it in a way that’s constructive, actionable, and motivating.
His coaching played a pivotal role in my development as a commercial leader—and any organization or individual looking to grow through clarity and thoughtful challenge would benefit from his guidance.”
Laura Kightlinger
Founder, Mindfuel -
"Nathan changed the way I think about leadership and driving results. He knows how to quickly create a focused, motivated, and aligned culture - getting individuals and teams to perform at their best by rallying them around the right goals. He brings a rare mix of operational excellence, business insight, and coaching ability. Everything is rooted in data and clarity, but he also knows how to stretch your thinking and push boundaries in a supportive way. I learned so much from working with him - about how to lead, how to prioritize what matters, and how to build teams that thrive, and I still apply those lessons every day."
Tim Rehm
Director of Customer Success, Attentive -
“Nathan’s leadership fundamentally changed the trajectory of my career. He brought clarity, vision, and perspective to our team, creating a culture where growth and excellence were not just possible—they were expected.
He saw potential in me before I saw it in myself. He encouraged me to take on more, guided me through pivotal decisions, and coached me into the leader I am today. I’m a stronger, more confident professional because of him—and a better mother, wife, and friend because of the personal growth his coaching inspired.
Nathan’s combination of strategic thinking and deep emotional intelligence made all the difference—not just in team performance, but in the development and well-being of the people he leads.”
Annika Kaufman
Regional Director of Commercial Sales, Smartsheet -
“Working with Nathan has been a transformative experience. His guidance improved how I interview, hire, and support my team—and helped me become a more strategic, confident leader. He taught me how to use data to uncover root problems, drive meaningful solutions, and develop reps more intentionally. Our team’s performance has measurably improved thanks to his insight and partnership.”
Caleb Thompson,
Regional Manager, Smartsheet -
“Nathan has an unmatched ability to develop talent and enable salespeople to perform at their highest level. As someone who was once on his team, and now works in sales enablement myself, I’ve seen how his coaching, clarity, and strategic mindset help reps not just hit their goals—but grow into confident, capable professionals.
As a consultant, Nathan brings that same intentionality to helping companies build the systems, messaging, and management practices that empower reps to succeed. If you’re looking to uplevel how your team sells and how your leaders lead—he’s the partner you want.”
Paul McGhee
Revenue Enablement Director, Clari -
“Partnering with Nathan to build high-performing teams was one of the most rewarding experiences of my career. He brought deep strategic insight to every hiring decision—always balancing what the business needed with a genuine care for people.
Nathan doesn’t just build strong teams—he builds strong individuals. He served as both a recruiting partner and a mentor, and his ability to listen, challenge, and lead with empathy left a lasting impact on how I show up in my own career. If you're looking for someone to help define talent, grow leaders, and shape culture, Nathan does all of it—and does it exceptionally well.”
Maggie Gilbert
Senior Recruiter, Smartsheet
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