Criminal defendants cannot successfully sue their criminal defense attorneys if they are striving to show that their criminal conviction was a result of legal malpractice.  This is a principle set forth by the Court of Appeals in Carmel v. Lunney.  

However, Sehgal v DiRaimondo 2018 NY Slip Op 06619 [165 AD3d 435]
October 4, 2018 Appellate Division, First Department. shows that there can be interesting variations in which claims might still exist.

“Plaintiff, a lawful permanent resident of the United States since 1998, pleaded guilty in 2014 to certain violations of federal election laws and was sentenced to one year probation. He alleges that he separately sought advice from defendants, who are specialists in immigration law, concerning the immigration consequences of his plea. Defendants provided a legal memorandum in which they advised plaintiff that it was unlikely he would be deported as a result of his plea and that, if he were placed in removal proceedings, he could seek a waiver from inadmissibility. Plaintiff alleges that, in reliance on the advice, he pleaded guilty and later traveled abroad. Upon his return to the United States, plaintiff was detained, placed in removal proceedings, and incarcerated for approximately four months.”

“We affirm dismissal of part of the malpractice claim on alternative grounds. Plaintiff’s claim that he pleaded guilty to criminal charges in reliance on defendants’ negligent legal advice concerning the immigration consequences of the plea is barred by his guilty plea and lack of any claim of innocence (Carmel v Lunney, 70 NY2d 169, 173 [1987]; Yong Wong Park v Wolff & Samson, P.C., 56 AD3d 351 [1st Dept 2008], lv denied 12 NY3d 704 [2009]).

However, the policy underlying the rule established in Carmel v Lunney, does not require dismissal of the entirety of plaintiff’s legal malpractice claim, because the remainder of his claim that defendants failed to advise him of the potential immigration consequences of traveling outside the United States as a result of entering a guilty plea does not dispute the validity of his conviction (see generally Carmel v Lunney; see also Bass & Ullman v Chanes, 185 AD2d 750 [1st Dept 1992]). Further, plaintiff’s allegations that he relied on defendants’ faulty legal advice concerning the immigration consequences of his guilty plea in deciding to travel abroad after he pleaded guilty, resulting in his being detained and subjected to removal proceedings, state a valid cause of action for legal malpractice. Defendants’ other [*2]arguments present disputed factual issues concerning the standard of care and proximate cause that are not properly resolved on a motion to dismiss the complaint (see Urias v Daniel P. Buttafuoco & Assoc., PLLC, 120 AD3d 1339, 1343 [2d Dept 2014]). Concur—Friedman, J.P., Sweeny, Kapnick, Gesmer, Singh, JJ.”