Williams, the founder and erstwhile team principal of the British team, died on Sunday, aged 79.
Williams was part of the sport’s fabric for more than half-a-century. He oversaw 114 wins, as well as seven drivers’ and nine constructors’ world championships.
“Frank was one of the old-timers who went back an awful long way,” Ecclestone, who ruled F1 for 40 years, told the PA news agency.
“One wonders that if people like Frank had not been around in the early days whether Formula One would have survived today. He was one of the people that built Formula One.
“It’s the end of an era.”
Williams’ achievements were made all the more remarkable following a road car accident in 1986 which left him in a wheelchair for the rest of his life.
Until his death, he was recognised as the world’s oldest surviving tetraplegic.
Williams was knighted in 1999 but his team were never able to replicate their heyday of the 1980s and 1990s. His daughter Claire assumed the day-to-day running of the team in 2013.
Williams became an irregular fixture in the F1 paddock in recent years, and at last season’s Italian Grand Prix in Monza the Williams family contested its 739th and concluding race after selling up to Dorilton Capital. Claire soon left her post as deputy team principal.
Ecclestone, 91, added: “Claire phoned me this morning to say we had lost Frank which I was happy and unhappy about. He had done so well for so long. But maybe these things are a blessing in disguise.
“She was obviously upset and we all knew this would happen before long.
“They called her yesterday to the hospital and said you ought to come and see him because he doesn’t have long to be with us. But I asked if he suffered at all and she said no, he didn’t.
“His story is incredible. Nobody lived as long as him in his condition [as a tetraplegic].
“But Frank never complained. He never whined and grizzled. He got on with things the best he could. He was a fighter. Frank was just Frank. He gelled with everyone and everyone liked him.”
Reigning Formula One world champion Lewis Hamilton tweeted: “Sir Frank Williams was one of the kindest people I had the pleasure of meeting in this sport.
“What he achieved is something truly special. Until his last days I know he remained a racer and a fighter at heart. His legacy will live on forever.”
Three-time world champion Sir Jackie Stewart described Williams as a “great man” and said he would love to have driven for him.
Stewart told Sky Sports News: “We will miss him always. He was a great man for British motorsport and always did the right thing.
“I never had the privilege of driving for Frank and I would love to have done it because he was a great man and a very good team owner.
“I raced against him from time to time and he was a competitor of the highest level.”
At the 1979 British Grand Prix, Alain Jones registered Williams’ first pole position before team-mate Clay Regazzoni took the team’s maiden win a day later. In 1980, Jones delivered Williams their first title.
Nigel Mansell and Damon Hill both won championships in a Williams car. Triple world champion Ayrton Senna also drove for Williams before his death at the 1994 San Marino Grand Prix. Williams was charged with manslaughter for Senna’s death but was acquitted several years later.
Hill, the 1996 world champion, told Sky Sports: “Frank was just remarkable in every respect with his dedication to the team. His record will stand for a very long time.
“The only person I could compare him to is [Ferrari founder] Enzo Ferrari. He loved Formula One and he loved racing. Anyone who runs a team would like to aspire to his achievements and to his record.
“He was a man of few words. He could speak many languages but he didn’t really engage in idle gossip. He’s a huge part of the history of the sport.”
In a statement, the Williams team said: “It is with great sadness that on behalf of the Williams family, the team can confirm the death of Sir Frank Williams CBE, founder and former team principal of Williams Racing, at the age of 79.
“After being admitted into hospital on Friday, Sir Frank passed away peacefully this morning surrounded by his family. Today we pay tribute to our much-loved and inspirational figurehead. Frank will be sorely missed.”
Briton George Russell, the Williams driver who will join Lewis Hamilton at Mercedes next season, said: “Today, we say goodbye to the man who defined our team. Sir Frank was such a genuinely wonderful human being and I’ll always remember the laughs we shared.
“He was more than a boss, he was a mentor and a friend to everybody who joined the Williams Racing family and so many others.”
Stefano Domenicali, F1 chief executive and former Ferrari team principal, said: “Frank was a true giant of our sport that overcame the most difficult of challenges in life and battled every day to win on and off the track.
“We have lost a much loved and respected member of the F1 family and he will be hugely missed. His incredible achievements and personality will be etched on our sport forever. My thoughts are with all the Williams family and their friends at this sad time.”