On November 3, 2021, President Joe Biden nominated Castner to serve as a United States district judge of the United States District Court for the District of New Jersey.[3] President Biden nominated Castner to the seat vacated by Judge Jose L. Linares, who retired on May 16, 2019.[5] Castner was recommended by Senator Robert Menendez.[6] On December 15, 2021, a hearing on her nomination was held before the Senate Judiciary Committee.[7] On January 3, 2022, her nomination was returned to the President under Rule XXXI, Paragraph 6 of the United States Senate;[8] she was later renominated the same day.[9] On January 20, 2022, her nomination was reported out of committee by a 12–10 vote.[10] On March 16, 2022, the Senate invoked cloture on her nomination by a 49–46 vote.[11] On March 31, 2022, her nomination was confirmed by a 52–47 vote.[12] She received her judicial commission on April 5, 2022.[13] She was sworn into office on April 7, 2022, becoming the youngest female district judge for the District of New Jersey.[14]
Personal life
Castner is married to Democratic lawyer Bill Castner. In 2018, Democratic Governor Phil Murphy named Bill Castner as his senior adviser on firearms.[15]