She graduated from Winston Churchill High School and later attended the Washington Semester program at American University in 1981, and Vassar College, where she earned a Bachelor of Arts degree in political science in 1983.

[9] In the Democratic primary, Kagan faced off against state delegate Luiz R. S. Simmons, whom she criticized for blocking domestic violence legislation and for being initially elected to the legislature as a Republican.

[1] In March 2018, Kagan accused lobbyist Gilbert J. Genn of inappropriately touching her back and buttocks during a karaoke event at the Castlebay Irish Pub in Annapolis, Maryland.

[20] In 2020, Kagan unsuccessfully ran for delegate to the Democratic National Convention, pledged to former New York City mayor Michael Bloomberg.

[1] Kagan was married to David Spitzer, a Montgomery County public school teacher whom she met at a concert in Rockville, Maryland.

[28][29] From 2017 to 2020, Kagan hosted the UnNaugural folk music concert at Montgomery College to raise funds for advocacy groups, including the ACLU, CASA de Maryland, and Planned Parenthood.

[38] During the 2020 legislative session, Kagan introduced a bill to delay the rollout of the state's absentee canvass, citing "election vulnerabilities and fiscal implications".

[40] In July 2020, Kagan criticized Hogan's decision requiring voters to apply for an absentee ballot to vote by mail in the 2020 general elections.

[50] At the time of the bill's introduction, roughly 25 percent of the legislature was initially appointed to their seats through the party central committee process.

[56] In February 2019, Kagan was one of six Democratic state senators to vote to confirm Governor Larry Hogan's nominees to the Handgun Permit Review Board.

[57] In November 2023, Kagan and eight other state senators signed a joint letter that threatened to defund immigrants rights group CASA de Maryland because it had called for an immediate ceasefire in the 2023 Israel–Hamas war and condemned the "utilization of US tax dollars to promote the ongoing violence.

[61] In September 2018, Kagan penned a letter to Governor Larry Hogan calling on him to open a state investigation into sexual assault allegations made against Supreme Court nominee Brett Kavanaugh.

[63] In January 2019, Kagan was one of nine Maryland lawmakers to add their names to a manifesto signed by 326 state legislators to reaffirm their commitment to protecting abortion rights.

[70] In July 2016, after the Washington Metropolitan Area Transit Authority (WMATA) closed the Red Line to make SafeTrack repairs, Kagan wrote to the Maryland Department of Transportation asking the agency to cover costs associated with the county's plan to provide free shuttle bus services to help commuters affected by the transit line's downtime.

[71] In July 2019, she criticized the Maryland Department of Transportation for withholding $55.6 million in funding for WMATA, which she predicted would have a "ripple effect" on the District of Columbia and Virginia.