After the Supreme Court struck down President Biden’s plan to cancel billions of dollars in student loan debt, borrowers wondered how he would make good on his promise to tackle debt burdening millions of Americans.

The answer: He would do it bit by bit.

Mr. Biden on Wednesday canceled $1.2 billion in student loan debt, bringing the total amount that he has wiped out during his time in office to $138 billion for 3.9 million borrowers. It is a far cry from his initial plan, which would have canceled up to $400 billion in debt for about 43 million borrowers.

But even Mr. Biden’s critics acknowledge that he has gone further than any of his predecessors in relieving the debt burden for millions of borrowers.

“It’s good for the economy as a whole,” Mr. Biden said on Wednesday, speaking to a small crowd at a library in Culver City, Calif. “By freeing millions of Americans from the crushing debt of student loan programs, it means they can finally get on with their lives.”

To work around the Supreme Court decision, Mr. Biden has pursued a more piecemeal approach, tweaking existing programs long plagued by bureaucratic delays. The debt cancellation he announced on Wednesday was an example of that, affecting about 150,000 borrowers enrolled in what is known as the SAVE plan, an income-driven repayment program, who have lower balances and have made payments for at least a decade.

While his administration has periodically announced such limited forms of debt cancellation in the past year, Mr. Biden’s stop to personally address the issue during a fund-raising swing through California appeared to reflect a White House intent on getting more credit for it. Democratic allies have been pleading for the administration to emphasize debt cancellation to galvanize crucial constituencies, including the young voters and Black borrowers who disproportionately shoulder such debt.

“The most common experience of student debt statistically is you file for relief, you thought you were going to get it and then the Supreme Court knocked it down and Biden is touting relief and you didn’t get any relief,” said Braxton Brewington, the press secretary for the Debt Collective, an advocacy group focused on student debt cancellation.

Representative James E. Clyburn, a South Carolina Democrat who helped resurrect Mr. Biden’s ailing 2020 primary campaign, said he was concerned that so many voters were focusing on the sprawling package Mr. Biden had failed to deliver rather than what he had done.

“Everywhere I went, students were saying to me, ‘Joe Biden didn’t keep his promise on student debt relief,’” Mr. Clyburn said. “Nobody was talking about the successes.”

The struggle illustrates a broader challenge facing the White House, according to interviews with Democratic officials, loan relief advocates and voters. In many ways, Mr. Biden has become a victim of the high expectations set by his initial sprawling proposals, leaving many voters disappointed over what he has failed to pass even as he has notched substantial policy wins on a number of fronts.

The president made the most ambitious investment to combat climate change in history, but polls have found that most Americans are unaware of his signature climate law. Despite a major stimulus bill and large investments in infrastructure and health, voters believe he has not accomplished much. And even many voters who supported Mr. Biden in 2020 are not impressed with the economy, despite falling inflation falls and unemployment near historic lows.

But Mr. Biden’s aides believe the student debt cancellation can be a way to quickly improve the lives of some Americans and help turn the tide on his low approval numbers.

The more limited measures have helped public service workers and those with disabilities. Last week, the Education Department also released a proposal that would cancel student debt for additional borrowers who experience “hardship” in paying off college loans.

In the round announced on Wednesday, people in the SAVE plan who originally borrowed up to $12,000 and who have made at least 10 years of qualifying monthly payments will have their debt wiped out.

In a sign of the struggle to get credit for the efforts, the administration sent an email from Mr. Biden to affected borrowers on Wednesday letting them know their debt would be erased this week.

“If you qualify, you’ll be hearing from me shortly,” Mr. Biden said.

Mr. Brewington said Mr. Biden’s workaround approach had been “better than any other administration” on student debt.

But he said it would be challenging for Mr. Biden to convince voters that he had delivered on student debt commitments when only a sliver of the tens of millions of people who initially thought they might benefit have had their debt canceled.

The fact that Mr. Biden took more than a year to announce his broad plan to forgive student debt only raised expectations among voters, Mr. Brewington said. After forecasting that he would cancel some student debt during the 2020 campaign, Mr. Biden agonized over the decision, repeatedly pressing his staff members for data showing that it would not be a giveaway for the wealthy.

“I get they want to talk about the work they’ve done on student debt, and I think they’re trying to have some nuance, but to a degree, it’s just not going to land with so many people,” Mr. Brewington added. “Especially when you’re saying ‘promises kept.’ I mean, good gracious.”

Mr. Biden’s ability to energize voters over the student debt cancellation is also made more difficult by the tumultuous rollout of a new Free Application for Federal Student Aid, or FAFSA. Delays and glitches have hampered colleges’ ability to offer aid packages that millions of students — particularly low-income students — rely on to make college decisions.

Republicans have seized on that bungled rollout to accuse the White House of prioritizing campaign promises over carrying out policy.

In a letter sent to Education Secretary Miguel A. Cardona last month, Representatives Virginia Foxx of North Carolina and Burgess Owens of Utah accused the department of focusing “its time and resources on transferring student debt to taxpayers rather than on faithfully implementing the laws enacted by Congress.”

To show the effect of his student loan relief efforts, Mr. Biden made an unannounced campaign stop last month at the home of Eric Fitts, a 49-year-old educator in North Carolina who had about $125,000 in student loans canceled. Rather than pay the debt, he plans on investing in the college fund for his two sons — who ate with Mr. Biden — and starting a real estate business.

Speaking of his debt, Mr. Fitts said he told Mr. Biden “how much of a burden it was and how much of a barrier it was for certain things and opportunities.”

But Ashley Pizzuti, a student debt relief advocate chosen by the administration to help negotiate on a regulation for more forgiveness, said she understood why Mr. Biden was facing more frustration than praise over student loans.

“There’s a lot of really upset people rightfully because they were told they were going to get this forgiveness and it was taken back,” Ms. Pizzuti said of Mr. Biden’s plan that was blocked by the Supreme Court. “And a lot of people blame Biden for that.”

The result, Ms. Pizzuti said, is “he didn’t live up to what he said he would live up to.”

Erica L. Green contributed reporting from Washington.