WASHINGTON — Timothy J. Sloan went to Capitol Hill on Tuesday to convince members of Congress that Wells Fargo had become a better bank.

By the time he left, it was clear that few believed him.

Mr. Sloan, the bank’s chief executive, fielded intense criticism during four hours of testimony before the House Financial Services Committee. Democrats and Republicans alike grilled Mr. Sloan, whose bank has tried to recover from a series of scandals in 2016, when it was revealed that Wells had been opening phantom bank accounts in customers’ names and forcing unnecessary fees and products on some of them.

His responses managed to draw ire even from officials who weren’t in the room: A spokesman for the bank’s primary regulator, the Office of the Comptroller of the Currency, released a statement on Tuesday saying officials were “disappointed” in the bank.

Mr. Sloan was the first in what is expected to be a parade of bank executives summoned to testify before the committee about the health of the industry now that Democrats control the House of Representatives. But their Republican counterparts also pulled few punches.