Due to national team commitments for the FIFA U-19 Women's World Cup in Thailand in the fall of 2004, Harris delayed her enrollment and did not start training with the Tar Heels until the spring of 2005.

[28] During her time with Athletica, Harris trained alongside United States women's national team starting goalkeeper Hope Solo.

[42] On February 23, following the allocation, Harris announced that she would be leaving her previous club, FCR 2001 Duisburg, and returning home in order to play in the newly formed NWSL.

They joined United States national team members Christen Press and Meghan Klingenberg, who were already with the club on long-term contracts.

[52] Harris confronted Boston Breakers forward Jazmine Reeves and referee Dimitar N. Chavdarov stepped in to end to altercation.

[80][81] On April 18, 2002, United States U-19 national team head coach Tracey Leone named Harris to the 18-player roster for the CONCACAF qualifying tournament.

[87] Following the training camp, Harris was subsequently named to the U-19 team that would represent the United States at the 2002 FIFA U-19 Women's World Championship in late August.

[104] In October 2003, Harris joined the U-19 women's national team for a training camp at the Home Depot Center in Carson, California.

[108] Harris was a member of the U-19 national team that played in the Philips Lighting U-19 Women's Soccer Invitational, their first major domestic tournament, from April 6 to 10.

[111] On April 28, Harris was named to the 18-player roster that would represent the United States at the CONCACAF U-19 Women's Qualifying Tournament held in Ottawa and Montreal, Canada.

[114] Harris recorded her second shutout of the tournament on June 1 during the team's final group match against Costa Rica, which ended in a 0–0 draw.

[119] Harris delayed her enrollment at the University of North Carolina at Chapel Hill in order to train with the U-19 team leading up to the U-19 World Championship in a modified residency program.

[122][123] Harris started in net in the opening group match against South Korea on November 11 and recorded a shut out for a 3–0 win.

I am just going to keep doing what I have been doing, training hard, and improving every day.On September 7, 2010, United States women's national team head coach Pia Sundhage named a 30-player roster for two matches against China in October.

[134] Although Harris was not one of the four goalkeepers on this preliminary roster, she was called into camp on September 23 to replace Hope Solo, who was recovering from a shoulder surgery.

[149] Following the 2012 CONCACAF Olympic Qualifying Tournament, Harris joined a 28-player roster for a training camp in Frisco, Texas in the week leading up to a match against New Zealand on February 11, although she did not suit up for the game.

The team's starting goalkeeper Hope Solo was out with a wrist injury, giving Harris the opportunity to make an appearance in the tournament.

She was put in a few difficult situations during the game and I think she handled them extremely well.Harris stated that she had "waited a long time for [that] moment" and although she was nervous, she was happy with her performance.

[175] She returned to the national team for a training camp at the end of August in order to prepare for two matches against Mexico in September as well as the 2014 CONCACAF Women's Championship in October.

United States starting goalkeeper Hope Solo was out on suspension during the matches, giving Harris the opportunity to make an appearance.

[192] Harris joined the national team on a Victory Tour following their World Cup win that started in Pittsburgh, Pennsylvania on August 16 and ended in New Orleans, Louisiana on December 16.

[217] Off the field, Harris is known for her distinct sense of style and extensive tattoos and has professed having interests in fashion, music, surfing, and skateboarding.

[222] Harris has publicly shared her experiences with depression, aggression, and Adderall addiction as a youth and young adult, and is heavily involved with the mental health-focused non-profit To Write Love on Her Arms.

[223] In May 2016, Harris spoke out in support of Aniya Wolf, a teenager from Pennsylvania who had been barred from her Catholic high school's prom after planning to wear a suit.

[224] A Central Florida native, Harris has on a number of occasions expressed support for the victims, families, and communities affected by the June 2016 massacre at the Pulse nightclub in Orlando.

[225] Like many of her U.S. women's national team teammates, Harris has spoken of the sexism faced by female athletes and the importance of improving their pay and conditions.

[226] In December 2016, Harris and national team coach Jill Ellis travelled to Liberia as part of the U.S. State Department's Sports Envoy program.

In addition to participating in meetings with government officials in support of women's sports, Harris and Ellis worked closely with students at the Monrovia Football Academy.

[227] While Harris does not have formal coaching experience, she has led goalkeeper training sessions in conjunction with Orlando Pride teammate Ali Krieger's youth camps.

[235] She has been in a relationship with actress Sophia Bush since 2023 and they made their red carpet debut at the 2024 White House Correspondents Dinner in Washington, DC.