In 1991, she became a partner with Sherr, Joffe & Zuckerman, P.C., and chaired the firm's domestic relations department.
Hired as a senior member of Cozen O’Connor in 1998, she co-chaired that firm's family law department.
[3][14][8] On August 28 and 31, 2015, Gantman approved twenty search warrants that were filed by Montgomery County prosecutors during their investigation of Pennsylvania Attorney General Kathleen Kane for perjury, obstruction of justice and related charges.
[16][17] In 2016, Gantman wrote the opinion of a three-judge panel that overturned a sanction issued by a Common Pleas judge against a medical malpractice attorney.
[18] On April 14, 2022, Gantman was appointed to a four-year term on Pennsylvania's Judicial Conduct Board.