Antonina Jadwiga Siemaszko (born July 14, 1970) is an American actress, best known for her film roles in Little Noises (1991), The Saint of Fort Washington (1993), and for her role as Eleanor Bartlet in The West Wing (2001–2006).
Siemaszko was born in Chicago. Her father, Konstanty Siemaszko, was a Polish-born Roman Catholic, and a survivor of the Polish Underground and the Sachsenhausen concentration camp. He escaped to the United Kingdom where he met Nina's mother, Collette McAllister. One of her brothers is actor Casey Siemaszko. Her other brother, Corky, is a writer for the Daily News and a reporter at NBC News. She attended The Theatre School at DePaul University. She played an undercover cop in Reservoir Dogs featured in a scene that wound up on the cutting room floor ensuring that the work became a rare example of a film containing no dialogue delivered by an actress. It was released on DVD. She played Mia Farrow in the CBS miniseries Sinatra. She played the leading role in Wild Orchid II: Two Shades of Blue. Nina Siemaszko(1970년생, Chicago, Illinois, USA) 는 배우로, 대표작으로 세인트 오브 뉴욕, Red Shoe Diaries 3: Another Woman's Lipstick, 와일드 오키드 2가 있으며, 그 외에도 그레이 아나토미, CSI: 라스베가스, 로 앤 오더: 크리미널 인텐트, 웨스트 윙, 콜드 케이스, FBI 실종수사대, Chicago Hope, American Playhouse, Judging Amy, 프라이빗 프랙티스, 테일즈 프롬 더 크립트, 가디언 등 다양한 작품에 출연했다. (오뜨랑에서 실시간으로 번역된 한글 프로필도 확인할 수 있어요) 2025년 더 페이퍼에 출연했다. 2018년 Hailey Dean Mysteries: A Will to Kill에서 Olivia 역을 맡았다. 2017년 The Hatred에서 Miriam 역을 맡았다.