Billionaire Richard Branson believes success is about happiness.
Though Sir Richard Branson, founder of the Virgin Group, is worth some $5 billion, the Virgin founder equates success with personal fulfillment.
"Too many people measure how successful they are by how much money they make or the people that they associate with," he wrote on LinkedIn. "In my opinion, true success should be measured by how happy you are."
Huffington Post co-founder Arianna Huffington says that money and power aren't enough.
Huffington says that while we tend to think of success along two metrics — money and power — we need to add a third.
"To live the lives we truly want and deserve, and not just the lives we settle for, we need a Third Metric," she told Forbes' Dan Schawbel, "a third measure of success that goes beyond the two metrics of money and power, and consists of four pillars: well-being, wisdom, wonder, and giving."
Together, those factors help you to take care of your psychological life and truly be successful, or as the title of her 2014 book, "Thrive," suggests.
Billionaire investor Mark Cuban says you don't need money to be successful.
"Shark Tank" regular Cuban offers a surprisingly simple take on success.
"To me, the definition of success is waking up in the morning with a smile on your face, knowing it's going to be a great day. I was happy and felt like I was successful when I was poor, living six guys in a three-bedroom apartment, sleeping on the floor."
Legendary basketball coach John Wooden said it's a matter of satisfaction.
"Warren Buffett has always said the measure [of success] is whether the people close to you are happy and love you."
He added: "It is also nice to feel like you made a difference — inventing something or raising kids or helping people in need."
Spiritual teacher Deepak Chopra believes success is a matter of constant growth.
The physician and author says it's a matter of continual growth.
"Success in life could be defined as the continued expansion of happiness and the progressive realization of worthy goals," Chopra writes in "The Seven Spiritual Laws of Success."
President Barack Obama aims to change people's lives.
Obama once held the highest office in the land — but he doesn't equate power with success.
At the 2012 Democratic National Convention, First Lady Michelle Obama told the audience that her husband "started his career by turning down high-paying jobs and instead working in struggling neighborhoods where a steel plant had shut down."
She went on:
"For Barack, success isn't about how much money you make. It's about the difference you make in people's lives."