Hammer first established herself professionally in New York as an original programming executive at Lifetime Television Network, where she executive produced several award-winning documentaries for the network's acclaimed Signature Series; she was honored with the Lillian Gish Award, several Cine Golden Eagles[5] and the National Association for Youth's Mentor Award.

[6] During the Monday Night War WWF ratings slump, Hammer was influential in stalling plans to cancel WWF Raw, and a cancellation was ultimately prevented after Barry Diller, a mentor to Hammer,[7][8] acquired the USA Network before Raw's contract with the network could expire in May 1998.

The project, a twenty-hour miniseries about alien abductions, garnered the best ratings Sci-Fi had seen to date and earned the channel its first major Emmy.

[8][16][17] While at USA Network, Hammer spearheaded the “Erase the Hate” pro-social campaign, which earned a National Emmy Governor's Award.

[18] She later extended it to create “Characters Unite,” a public service program to combat hate and discrimination and promoting tolerance and acceptance.

Under Hammer's leadership, Characters Unite has grown into an award-winning, multi-platform initiative that includes on-air programming such as documentaries and themed episodes of USA series, public service announcements, digital content through the website and social media outlets, and community outreach and high school education programs, featuring a partnership with storytelling group The Moth.

Hammer also created the “Visions for Tomorrow” campaign, which is an effort to spark America's leading thinkers, organizations, and policymakers into searching for ways to solve society's most pressing issues.

[21][22][23] She was given the National Association of Television Programming Executives’ 2007 Brandon Tartikoff Legacy Award[24] and inducted into Broadcasting & Cable's Hall of Fame the same year.

[25] Hammer has also received a MUSE award for outstanding vision and achievement from New York Women in Film & Television.

[32] Praise for her social activism includes her 2012 honor by B’nai B’rith for “her commitment to initiatives confronting racism and bigotry’;[33] and she was cited by storytelling organization The Moth for “philanthropic leadership in programs to end prejudice, discrimination and bullying.” Hammer was given the 2010 Vanguard Award for Distinguished Leadership from the National Cable Television Association,[18] and the Anti-Defamation League's Entertainment Industry Award.