Joe Sims is the national co-chairman of the Communist Party of the United States of America (CPUSA), as well as a co-editor of the Party's online newspaper, People's World. He has held the position of co-chairman since 2019, when he was elected alongside Rossana Cambron at the party's 31st national convention in Chicago.^[1]

Joe Sims was the section chairman for the Young Workers Liberation League in Washington, D.C. when he attended the Communist Party USA's extraordinary conference in Milwaukee in April 1982.^[2]

Sims had the opportunity to participate in the World Federation of Democratic Youth festivals in Berlin in 1973, Moscow in 1985, and Pyongyang in 1989.^[3]

As of March 1994, Sims was a member of the Organization Commission of the Communist Party USA.^[4]

In March 1998, Sims was part of the “Endorsers of the Call” effort, founding the Black Radical Congress from the Communist Party USA.^[5] In 2000, Sims was the New York United contact for Black Radical Congress.^[6] In 2001, Sims served on the Black Radical Congress journal BRC Today editorial board.^[7]

On March 30, 2002, the Communist Party USA paper People's Weekly World called for a national holiday in honor of late United Farm Workers leader Cesar Chavez. The article was followed by a long list of endorsers including Joe Sims.^[8] Almost all endorsers were members of the Communist Party USA.

In 2009, he was publisher on the Editorial Collective of Political Affairs, theoretical journal of the Communist Party USA.^[9]

He traveled frequently to South Africa since the unbanning of the African National Congress and the South African Communist Party, and has written and reported extensively on South African developments.^[10]

He was a People's World Editorial Board Co-editor in 2015.^[11]

In June 2019, Sims and Rossana Cambron became co-leaders of the Communist Party USA.

In March 2021, CPUSA committee members Joe Sims, Zenobia Thompson, and Eric Brooks initiated the reform of the African American Equality Commission. According to Sims, the AAEC will "support the CPUSA National Committee, clubs, and members in maintaining a focus on outreach and recruitment in the Black community, help the CPUSA strengthen the theoretical framework for a Marxist/Leninist understanding of the current struggles of the Black community in the USA, and spotlight struggles to improve Black living conditions."