Is work-life balance dead in Silicon Valley? Here’s why top CEOs say 9-to-5 isn’t enough

In Silicon Valley and on Wall Street, the idea that working from 9 AM to 5 PM will get you to the top of the corporate ladder is increasingly being challenged. For a generation of young professionals hoping to balance ambition with a manageable lifestyle, the message from some of the world’s most influential chief executives is clear-cut: success demands more than a standard workweek.In an interaction with Fortune, Andrew Feldman, cofounder and chief executive officer of Cerebras, an $8.1 billion artificial intelligence chip company, said that believing one can achieve extraordinary outcomes while working a limited schedule is “mind-boggling.” He stressed that part-time efforts will rarely produce groundbreaking results, arguing that building something from nothing requires relentless focus and dedication.

The grindset culture persists

Despite growing discussions around shorter workweeks and flexible schedules, leaders across the US are reaffirming the value of sustained intensity. Google cofounder Sergey Brin, Shark Tank investor Kevin O’Leary, and others highlight that the path to launching industry-defining products or companies is rarely compatible with a conventional 40-hour workweek. Feldman told Fortune that while it is possible to maintain a fulfilling life on standard hours, those hours alone are unlikely to produce the next unicorn. The expectation for founders, he noted, is to commit “every waking minute” to their work, fully aware of the personal costs involved.

A consensus on hours and productivity

The myth of work-life balance has been repeatedly questioned by leaders at the top of their fields. Zoom CEO Eric Yuan has suggested that work and life are inseparable, while LinkedIn cofounder Reid Hoffman emphasized that launching a successful startup requires prioritizing work above distractions. Hoffman told Stanford University students in 2014 that founders who claim to maintain a balanced life are often not fully committed to their ventures, Fortune reports. Yet, even within Silicon Valley, extremes such as 100-hour workweeks are being reconsidered. Khozema Shipchandler, CEO of Twilio, told Fortune that he allows himself just eight hours on Saturdays to step away from work. He acknowledged that work-life choices are personal, but noted that few peers maintain a traditional nine-to-five schedule. Other high-profile figures, from tennis champion Serena Williams to multimillionaire Kevin O’Leary, have described the demands of entrepreneurship as exceeding the limits of a standard day. Yet Brin recently advised Google Gemini employees that a 60-hour workweek represents a “sweet spot” for productivity, reinforcing the notion that going beyond the standard schedule is often necessary.

Focus, not hours

Experts caution that there is no universal formula for success. According to workplace specialists speaking with Fortune, the focus should be less on a set number of hours and more on completing work effectively. Feldman echoed this sentiment, emphasizing that passion and commitment — not time logged — drive meaningful outcomes. For leaders seeking impact, the challenge is not merely to work longer but to be fully engaged and driven to advance their vision while supporting their teams.

Lessons for ambitious professionals

The experiences of these Silicon Valley leaders illustrate a fundamental tension between personal balance and professional ambition. For those aspiring to the C-suite, the standard hours are unlikely to yield extraordinary results. Instead, dedication, focus, and willingness to extend effort beyond conventional limits remain defining traits of high-performing founders and executives. While the debate over work-life balance continues, the perspective emerging from Silicon Valley suggests that 9-to-5 schedules may be insufficient for those aiming to build transformative companies. According to them, the conversation is not about eliminating personal time entirely but understanding that achieving the next generation of innovation requires a commitment that extends well beyond the clock. But, is relentless work really the price of success?