The question entangles two concepts that are not identical.

The standard of recovery for malpractice is negligence. Negligence could involve omissions. But, it could also involve positive act, for example, introducing evidence or asking a question at trial or making an objection that is unintentionally harmful to the client that a reasonably competent attorney would not have done.

Intentional conduct can give rise to claims for punitive damages in what would otherwise be a pure negligence claim. But intentional conduct can involve omissions as well as commissions, such as intentionally not introducing evidence in the possession of an attorney that would exonerate a client because the attorney is annoyed with the client.

In addition to malpractice liability to a client, lawyers face potential sanctions from a court for misconduct, potential ethical sanctions implicating the lawyer's license, and civil actions for breach of fiduciary duty (e.g. in a conflict of interest case) that can result in forfeiture of fees. These kinds of non-malpractice consequences can also arise from both acts and from omissions. They are more likely to involve intentional conduct, but this isn't necessarily the case. Mismanagement of a trust account can result in serious sanctions in the absence of intentional conduct, and it isn't that hard to back into a conflict of interest either.

The question entangles two concepts that are not identical.

The standard of recovery for malpractice is negligence. Negligence could involve omissions. But, it could also involve positive acts, for example, introducing evidence or asking a question at trial or making an objection that is unintentionally harmful to the client that a reasonably competent attorney would not have done.

Intentional conduct can give rise to claims for punitive damages in what would otherwise be a pure negligence claim. But intentional conduct can involve omissions as well as commissions, such as intentionally not introducing evidence in the possession of an attorney that would exonerate a client because the attorney is annoyed with the client.

In addition to malpractice liability to a client, lawyers face potential sanctions from a court for misconduct, potential ethical sanctions implicating the lawyer's license, and civil actions for breach of fiduciary duty (e.g. in a conflict of interest case) that can result in forfeiture of fees. These kinds of non-malpractice consequences can also arise from both acts and from omissions. They are more likely to involve intentional conduct, but this isn't necessarily the case. Mismanagement of a trust account can result in serious sanctions in the absence of intentional conduct, and it isn't that hard to back into a conflict of interest either.