Kimberly began her career working at Brown & Wood, LLP, a large firm in New York City. In 2002, she joined the Nassau County District Attorney's Office where she tried numerous cases to verdict. She joined her father Richard's practice in 2005.

At Lerner & Lerner, P.C., she handles most of the criminal matters, including felonies, misdemeanors, and traffic violations, and assists Richard with all other matters. She is also the head of the Nassau Bar Association's District Court Committee and has been assigned to a special task force investigating indigent client services. Kimberly has repeatedly lectured at the Nassau County Bar Association and recently was chosen by Senator Fuscillo to speak to high school students about DWI.

Kimberly is featured as a legal correspondent for Fox News, CNN, MSNBC and local television. She has appeared on numerous shows including The O'Reilly Factor, Hannity & Colmes, The Line Up, Scarborough Country, Live with Rita Cosby, Fox News Live, The Live Desk, Kendall's Court, Nancy Grace, The Big Story with John Gibson, The Strategy Room, Channel 12 News, NBC News, CBS News, and ABC News.