Oliver Gates is a defense attorney, regarded as a bottom-feeder among his peers. He loves to use variations of the insanity defense to get his clients off.
- Sean Webster (SVU: "Hate")
- Claimed that Webster was "hard-wired" to hate Arabs and Muslims after his father Seth was killed during the Gulf War, an assertion that seemed proven when Webster killed a Muslim while in holding; case fell apart after Gates discovered that Seth was, in fact, still alive, but had divorced Sean's mother after falling in love with a Kuwaiti woman. He'd tried for years to get back in touch with Sean and patch things up between them, but Sean's mother had told the boy that Seth wanted nothing to do with them. In a sad irony, Webster was killed shortly after being reunited with his dad, by a gang of Muslims seeking to avenge their fallen brother.
- Karen Campbell (SVU: "Poison")
- Initially defended Campbell against charges of assault and attempted murder of her adopted daughter, Alexis (Karen had forced Alexis to drink over a cup of detergent). Successfully made motions to Judge Oliver Taft to suppress Katie Campbell, Karen's biological five-year-old daughter, from being a sworn witness and also from having her testimony admitted as evidence (which definitely would have convicted Karen). Gates then made one final motion: to waive the jury at Campbell's trial, ensuring that Judge Taft would be the only one deciding Campbell's fate; Taft promptly granted the motion despite ADA Casey Novak's objections. After hearing the arguments presented by the prosecution and defense, Judge Taft found Campbell not guilty on all charges.
- After the revocation of the conviction of Rosalin Silvo, Gates was retained by Campbell once again after she successfully murdered Alexis, who had been released from the hospital with severe brain damage from the initial detergent consumption. Gates tried to argue that Alexis's death due to her brain damage was collateral estoppel, so Cambell could not be retried; this theory was refuted by Detective Olivia Benson, who revealed that Alexis had died from suffocation, not brain damage, thus establishing a new case against Campbell separate from the first. Campbell responded by saying that Judge Taft had told her to do it, claiming that Taft had said that her family would be better off if Alexis was dead. Campbell then revealed that this conversation took place with the judge ex parte, prompting Gates to terminate her interview with Novak and the detectives while he got the rest of the facts from Campbell; Gates later denied having any knowledge of this ex parte communication to save himself from possible repercussions. It is unclear whether or not this is true. Campbell was subsequently tried and found guilty of murder in the second degree.
- Garrett Perle (SVU: "Game")
- Nicky Pratt (SVU: "Gone")
- Initially defended Pratt against charges that he'd raped and murdered a girl with his friends Doug Waverly and Jason King. When King decided to plead out, Pratt and Waverly kidnapped and killed him. Without Jason's testimony, they walked for the murder, but they did a poor job desposing of King's body - it got caught on a bridge. Pratt and Waverly were found guilty.
- Scott Heston (SVU: "Pretend")
- Argued that Heston's murder of Riley Cuskey was an accident arriving out of some very stupid behavior, but it was discovered during the course of investigation that Heston had desired Cuskey's girlfriend, Cassandra Sullivan, and decided to take a plea bargain. Later, it was discovered that Sullivan was nearly thirty years old, but had been posing as a teenager in foster care for years because she was quite literally afraid of growing up. Gates, never one to avoid an opportunity, convinced Heston to sue Sullivan for extreme emotional distress; the results of this suit are unrevealed.