Hon. Donald Pearl is a judge of New York Supreme Court, who made his sole appearance in "Errors and Omissions".
Donald made his only appearance in "Errors and Omissions", presiding over the patent dispute of Wyatt's satellite cell phone. As Harvey Specter entered the courtroom, turning off cell phone, he immediately berated Harvey for having his phone in his hand and for his lateness, fining Harvey $1,000 for "failing to follow the posted rules of the court".
When during the hearing opposing counselor petitioned him to dismiss the case, Harvey in turn presented a request for an injunction, but Pearl cut him off mid-sentence, and questioned why he had not been given a courtesy copy of the injunction. He denied his request for an injunction. After issuing the verdict, he angrily told Harvey "better luck next time". In his office, Harvey found out that the cause of Pearl's unwillingness to consider given argument was because he thought Harvey had an affair with his wife, Lauren. Although, it turned out, that she was tipsy and Harvey sent her home in a cab, refusing her flirting because she was married.
In exchange for injunction Pearl asked Harvey to sign a document confirming that he had adultery with Lauren, which would prevent her from claiming from taking half of Pearl's possession in planned divorce. He also said Harvey, that he is going to end the judicial career. However, at the end of the episode Harvey informed him that there is an investigation into the his attempt of blackmailing, suggesting that if he was willing to do it to him, he has probably done it before. Harvey also revealed that he never slept with his wife, but had not told him, because he would never believe it.