Renaud Laplanche was the quintessential Silicon Valley success story, until he wasn’t.

Mr. Laplanche, a French-born entrepreneur, co-founded Lending Club in 2006, creating not only a new company but also a new model for borrowing money online. He took Lending Club public late in 2014 and joined the ranks of the Silicon Valley elite.

Then last May, he was ousted abruptly from the company he had built. The board that he had put together turned up falsified loan records and conflicts of interest under Mr. Laplanche’s watch, and almost overnight, he was cast aside.

Now, less than a year later, Mr. Laplanche is attempting a comeback.

On Thursday morning, he is starting a new company, Upgrade, that will compete with Lending Club head-to-head.

Upgrade will begin by offering small loans to Americans who want to refinance credit card debt, the bread and butter of Lending Club’s business. The company’s goal is to move into home and auto lending eventually as well.

With Upgrade, Mr. Laplanche, 46, hopes to prove that his vision for changing the lending business can work. And at least some investors seem to believe that it can. Upgrade has attracted $60 million in financing from several prominent venture capitalists, including Union Square Ventures, which previously backed Mr. Laplanche at Lending Club.

Mr. Laplanche, in his first interview since leaving Lending Club, said that his sudden ouster had been “incredibly frustrating and disappointing” but that he had taken it as an opportunity to confront some of the problems he was unable to fix at Lending Club.

“I didn’t look for a fresh start, but we are trying to make the best out of it,” he said while sitting in a conference room in Upgrade’s offices, which are just a few blocks from the Lending Club headquarters in downtown San Francisco. “After 10 years there is a really long list of things where we said, ‘If we have the chance to do it all over again we would do it differently.’”

To set Upgrade apart from Lending Club and other competitors, the company, previously referred to in filings as Credify, will offer, among other features, free credit monitoring tools and financial education to keep customers engaged even if their initial loan applications are rejected.

The competition between Mr. Laplanche’s new company and his old one is notable if only because he remains one of Lending Club’s largest shareholders, with a stake worth about $40 million.

As he did at Lending Club, Mr. Laplanche is betting that by moving all sorts of borrowing online, start-ups can do away with the expensive physical branches that banks have traditionally relied on and reach more people, while make lending decisions more quickly and transparently.

Upgrade’s open-floor-plan offices were buzzing this week with almost 50 employees, including several who had been forced out of Lending Club with Mr. Laplanche.

Mr. Laplanche’s comeback, though, is not going to be easy to pull off.

The industry he helped invent is crowded now, with established banks like Goldman Sachs competing to issue personal loans online alongside Silicon Valley players like Prosper and Social Finance.

Even before Mr. Laplanche’s departure from Lending Club, there were questions about whether the fast-growing industry could continue to attract the money it needed from investors to finance all of its new loans, a problem that all such start-ups have because they do not have bank deposits to fund their lending.

Lending Club’s shares are now worth a quarter what they were worth when the company went public.

All of the issues facing the industry will be problems for Upgrade as well, but none will loom larger than the need to win over the investors necessary to finance Upgrade’s lending capabilities, many of whom were unnerved by Lending Club’s problems.

“There’s going to be a large contingent of investors who are going to need to see a longer track record before they entertain coming back,” said Michael Tarkan, an industry analyst at Compass Point.

Mr. Laplanche has already succeeded in winning the support of some big names in addition to Union Square Ventures, including Silicon Valley Bank. The $60 million raised by Upgrade is the largest Series A fund-raising round by an American lending start-up, according to data from CB Insights, and pegs the value of Mr. Laplanche’s company at $168 million.

John Buttrick, a partner at Union Square Ventures, said in an interview this week that before making the new investment he had taken a thorough look at the circumstances behind Mr. Laplanche’s resignation from Lending Club and had not found anything that gave him pause about backing Mr. Laplanche again.

“He has an opportunity to start Lending Club 2.0, and we are excited to be a part of it,” said Mr. Buttrick, who previously worked with Mr. Laplanche as a board observer at Lending Club.

In a particularly important vote of confidence, Jefferies, the Wall Street bank that bought some of the problematic loans issued by Lending Club last year, has already signed up to buy some of the loans created by Upgrade.

Mr. Laplanche’s sudden resignation last year came after the Lending Club board learned that millions of dollars of the company’s loans had been sold to Jefferies with errors and falsified dates.

The Lending Club board also said that Mr. Laplanche had not properly disclosed personal investments he had made in an outside fund that purchased Lending Club loans.

Mr. Laplanche, a former corporate lawyer, said at the time that he did not agree with the way the board characterized the problems, but he declined to say anything more about the events that led to his departure.

Those who backed both his new and old companies said they had been shocked by his resignation because Mr. Laplanche had stood out in the tech industry for his careful and deliberate approach.

“There are a whole bunch of cowboys in Silicon Valley, but Renaud is not one of them,” said Alexander Tamas, the founder of Vy Capital and the lead investor in Upgrade.

After the resignation, Mr. Laplanche took some time off with his family to go hiking in the Alps and visit his mother in southern France.

But he was also working the phones with investors and former colleagues at Lending Club. By August, he had rented an office to begin his new company with five Lending Club veterans as co-founders.

Unlike Lending Club, Upgrade will not sell its loans to small-time investors. Mr. Laplanche is looking only to big institutional money managers, and he said that he already had four large investors on board.

For customers, the biggest difference is likely to be the free credit monitoring and education, a service already popularized by the start-up Credit Karma.

Mr. Laplanche said that Lending Club had rejected nearly 90 percent of loan applicants and had then often lost touch with them. With the new service, Upgrade can help coach rejected applicants on how to improve their credit so they can eventually be approved for a loan from the company.

“We took the opportunity of what happened in May and the broader experience to really rethink every piece of the process and think of how we could build on it and improve on it,” he said.