With a loan from her father, Zach Lonstein, chief executive officer of Infocrossing, she started her clothing company in 1998 with the mission to design a clothing line that appealed to different body types, specifically, large-breasted young women.

[3][4][5] In 2013, Elizabeth Arden, Inc. named Gruss the brand's first-ever Style Director.

[6] Gruss has appeared in numerous television programs, webcasts, and interviews, including a 2008 episode of America's Next Top Model.

[9] Lonstein later came to public attention by dating Seinfeld, who was at the time starring in his eponymous sitcom.

[15] Gruss is a trustee of Reform synagogue Temple Emanu-El of New York,[16] and the Nightingale-Bamford School where she is also a member of its Alumnae Board Committee.