After the shooting of Trayvon Martin, Lewis protested for the first time, marching with her mother on Michigan Avenue. Lewis became further engaged while attending high school at Walter Payton College Prep, after attending primary school in the less-affluent, majority African American South Side. In 2015, when she was a junior in high school, Lewis founded the non-profit The I Project. The I Project supports intersectional activism through art, with fundraising and community outreach. Events have included a photo shoot for people of all sizes and shapes, with a discussion of culture and body image, and a screening of Beyoncé's Lemonade with inter-generational panel discussion. In 2016, Lewis joined three other black teen women activists to organize a youth sit-in in Chicago, to protest police shootings of people of color, particularly Alton Sterling and Philando Castile. The organizers rallied young community members on social media, with a Facebook event and the hashtag #BLMCHIYouth. The four organizers led a crowd of over 1,000 people in a peaceful sit-in in Millennium Park, and a march down Michigan Avenue and State Street. There were no arrests, a symbolic victory because of the reputation of violence in Chicago, especially among youth of color, and a strained relationship between anti-racism activists and Chicago police. Following the march, Lewis and the organizers started Youth for Black Lives to activate youth voices against systemic oppression. With Y4BL, Lewis organized a second march beginning in Millennium Park on August 7, 2016, to protest police brutality following the death of Paul O'Neal. In November 2016, in response to a deadly police shooting in Mount Greenwood, Chicago and racist text messages sent among students of Marist High School, Y4BL organized another march. However, Lewis and the organizers received threats on social media, and CPS leadership contacted the organizers parents, and the march was cancelled due to safety concerns. Instead, Y4BL organized meetings with Chicago Police Department Superintendent Eddie T. Johnson. The first, held on November 11, 2016, included Johnson, the Chief of Patrol, the Alderman of Mt. Greenwood, and the principal of Marist High School. During the first and subsequent meetings, Lewis and the other Y4BL members questioned Johnson and discussed racism and policing in Mt. Greenwood and Chicago at large.
Lewis contributed to Teen Vogue in 2016 and 2017, focusing on black women, intersectional feminism, and perceptions and approaches to handling violence in Chicago. She addresses social justice, especially for people of color.
