He is the chairman and CEO of Comcast, a multinational telecommunications and media company providing entertainment and communications products and services, founded by his late father, Ralph J. Roberts.

[7] In 1997, Roberts coordinated a deal with Bill Gates for Microsoft to invest $1 billion in Comcast, which supported the expansion of its broadband network.

[24] Additionally, Roberts was elected chairman of CableLabs, a research and development consortium for the cable industry, where he held the position for three consecutive terms[24] Institutional Investor Magazine named Roberts as its top vote-getter for three years in a row (2004–06) in the Cable & Satellite category of their America's Best CEOs annual survey; and named Comcast as one of America's Most Shareholder-Friendly Companies in 2006.

The Police Athletic League of Philadelphia honored Roberts with their 2002 award for his commitment to youth programs and community involvement.

[31] The following year, Roberts received the William Penn award, "the highest honor bestowed upon a business executive in Greater Philadelphia," according to the Chamber of Commerce.

[32] The Roberts family, led by Brian has made philanthropic contributions to various medical, educational, and cultural institutions.

[33] In 2016, the family provided a gift to support the creation of the Roberts Collaborative for Genetics and Individualized Medicine at the Children's Hospital of Philadelphia.

[34] In response to the COVID-19 pandemic in 2020, the Roberts family donated $5 million to the School District of Philadelphia to purchase Chromebooks for students to support virtual learning.

[40] In December 2009, Roberts wrote a letter to President Barack Obama, endorsing the Patient Protection and Affordable Care Act.