But after winning a third straight World Touring Car Championship last year, the Argentine felt the urge to change track -- to Formula E.
"I could have stayed in WTC probably to look for more wins and championships but that's not what I look for in motor racing," Lopez told CNN's Supercharged show.
"I want to keep growing and fighting with better drivers in various categories, and I think Formula E has all these things.
"It is growing so fast and you have fantastic drivers and teams. For me it was a step forward, so I'm really happy to have this challenge."
Like many drivers in the electric car series, he started out with high hopes of a career in Formula One.
After a year as a test driver for Renault, he was contracted to the ill-fated USF1 team in 2010 -- but it never made it to the starting grid.
Lopez bounced back from that disappointment, and dominated during four years in WTC with 29 wins and 48 podiums from 71 race starts. In two of those seasons he outshone high-profile Citroen teammate Sebastien Loeb, a record nine-time champion in the world rally series.
He has yet to make an impact in Formula E but the learning curve is steep -- temporary street circuits mean limited opportunities for track testing, and adjusting to electric powertrains takes time.
"The grip, the tires, the chassis, the weight, together makes the car very nervous and difficult to understand," Lopez told Autosport
ahead of the season-opening ePrix in Hong Kong last October.
A retirement followed in the race but there's been steady progress since -- a 10th-placed finish at November's Marrakech ePrix in Morocco was repeated at his home race in Buenos Aires last month.
Passion and drive
In April, he will be on more familiar ground in Mexico -- the fourth ePrix of the 2016-17 season will be staged at a traditional racetrack, the Autódromo Hermanos Rodríguez.
Lopez hasn't completely turned his back on petrol power either -- the 33-year-old is scheduled to compete in the 2017 World Endurance Championship
for the Toyota Gazoo Racing team.
"I have so much passion for what I do -- I love racing. When I jump in the car I feel different," he says.
"I always say this is my place in the world when I put my helmet on. I can isolate from everything and just focus and do what I do I like to do, and I'm lucky enough to do it as my work as well."
Despite all his success, "Pechito," as he is known to family, friends and colleagues, has managed to keep his feet on the ground.
So what's his secret?
"I am passionate but the years, the experience, has given me a little quietness," he says.
"I never believed I was a gifted guy. I like to believe that work, dedication and never giving up is very important -- that's what I have done in my career so far."