[2] She is best known for leading the California Golden Bears crew as varsity coxswain while fighting against stage IV lung cancer.

[3] During her year-long battle with cancer, Costello completed her degree in political economy of industrial societies with a 4.0 GPA, was the Cal Greek System's Panhellenic Vice President, was an active member of Kappa Kappa Gamma, raised hundreds of thousands of dollars for lung cancer research, and was an active member of Cal Bears women's varsity crew.

[3] She also coxed the varsity 8+ for her first time during the 2010 season and she led the Bears to a victory over Stanford to clinch the Pac-10 Championships for Cal.

However widespread the cancer, she was physically fit, a nonsmoking, college athlete, and had only gone to the trainers office with slight pains in her abdomen days after coxing her boat to a second-place finish at NCAA.

The gravely serious diagnosis she received from her initial stomach pain was shocking, and Costello's story spread quickly through her CaringBridge website.

[8] Soon after her diagnosis, she was interviewed on National Public Radio and spoke against the negative stigma surrounding lung cancer as a "smoker's disease".

[10] In April 2010, Costello held "I like my hair, but I LOVE my lungs" parties and encouraged friends from around the country to cut off their ponytails and donate them to the Pantene Beautiful Lengths cause.

[12] On June 20, 2010, four days before her death, Costello sent out a mass message on Facebook and her CaringBridge page from her hospital bed, inviting everyone she could to participate in the upcoming San Francisco BJALCF Walk in September in her honor.

It broke the record previously set by February 2010's jog, and is currently the largest event held in support of lung cancer research.

All money raised through the group's fundraising campaigns goes directly to young researchers and lung cancer awareness movements.

[21] Members of the group attended the International Association for the Study of Lung Cancer's[22] July 2011 World Conference in Amsterdam.

[23] Jill's Legacy has held local events in San Francisco and the Bay area, including a benefit party before the Cal v. Stanford Big Game in 2011.

[24] Cal Woman's Crew raced and won as "Team Jill" wearing special uniforms in honor of Costello at the "2010 Big Row" against rival Stanford.

[20] On June 5, 2011 ESPN's Beyond the Game aired a special feature on Costello entitled "Wave and Wake" by Jeff Freeman, documenting her inspirational effect on the Cal Women's crew, especially during their 2010 season.