Off the top of my head, I can’t recall anyone who did a COMPLETE 180, but I can cite 2 “disappointments” to their nominating presidents: Harry Blackmun and David Souter.

Harry Blackmun was nominated by Richard Nixon as a good friend of Chief Justice Burger, a conservative justice, and fully expected to adhere to a conservative interpretation of the Constitution. Initially, this was true, as Blackmun and Burger were the most closely aligned votes on the Court for the first 5 years of Blackmun’s tenure. However, Blackmun then took a hard shift to the left and became a reliable vote for the liberal bloc of the Court, most famously in his authoring of the majority opinion in Roe v. Wade.

David Souter was nominated by George HW Bush to replace William Brennan, and he was nominated having served less than a year in the federal circuit following his tenure on the New Hampshire Supreme Court. He had no significant paper trail of jurisprudence, which Bush saw as an asset following the failure of Reagan to nominate Robert Bork (Reagan, for that matter, had also considered Souter as a potential nominee). Bush ultimately nominated Souter, on the recommendation of New Hampshire Republicans, to the Court, presuming he’d be a conservative bloc vote. Souter certainly didn’t wind up being as liberal as Blackmun, but he was considered the ideological center of the Court for years, and often voted with the liberal bloc more consistently than the conservative bloc. He authored the three-person plurality opinion in Casey (along with 2 Reagan appointees), and sided with liberals on social issues such as school prayer, as well as on the famous Bush v. Gore case. This all despite losing the votes of many Democrats, such as Ted Kennedy, in his nomination process, being painted as a radical conservative jurist.

There are other potential examples, such as Reagan nominating Kennedy, who was consistently conservative but wound up being the key swing vote on the Court, and Eisenhower nominating Brennan, the most infamously liberal justice ever being nominated in part because he sounded conservative on issues of criminal justice, but Blackmun and Souter are probably the 2 most famous examples.