Sarah O'Brien is a serial entrepreneur and business strategy consultant with 13 years of experience founding, scaling, and advising startups, holding an MBA from Harvard Business School and having successfully exited two venture-backed companies in the SaaS and marketplace sectors, currently serving as strategic advisor to early-stage founders and leading workshops on execution discipline and organizational resilience.
Sarah O'Brien graduated with an MBA from Harvard Business School, where she concentrated in entrepreneurial management and strategic execution. She founded her first venture at age 28, a B2B SaaS platform that scaled to $10M ARR before acquisition by a larger enterprise software company. Her second venture, a two-sided marketplace, achieved product-market fit and raised Series B funding before a successful strategic exit. Over 13 years as a founder and operator, Sarah developed deep expertise in validating business ideas before committing capital, building high-performing teams with complementary skill sets, designing decision-making frameworks that empower teams without creating strategic drift, and executing strategies with precision to avoid the 70% failure rate of strategic initiatives. She now works as a strategic advisor to early-stage founders, helping them construct resilient business foundations, define measurable objectives that cascade into daily operations, and navigate the critical transition from side project to full-time venture. Sarah teaches at startup accelerators and business schools on topics including bootstrapping versus venture funding trade-offs, building antifragile organizations that strengthen under stress, conducting rigorous market analysis to uncover unmet needs, and maintaining execution momentum during the difficult middle phase of long-term initiatives. She is particularly expert in helping founders avoid the fatal mistakes that doom ventures before launch, such as targeting non-existent market segments or creating decision-making structures that fragment unity rather than build cohesion. Sarah is a frequent speaker at entrepreneurship conferences and contributes thought leadership to business publications on strategic execution, organizational design, and sustainable startup growth.