Feeney graduated from Don Bosco Technical High School.

He worked for Verizon as an office technician, and served as the legislative director for the International Brotherhood of Electrical Workers.

Feeney has also served as chief of staff for Jim Timilty and as labor director for Stephen F. Lynch's campaign for the United States Senate in the 2013 special election.

Feeney was state director of Connecticut and Massachusetts for the Bernie Sanders 2016 presidential campaign.

[1] When Timilty resigned in 2017, Feeney ran in the special election to succeed him, defeating Republican Jacob Ventura.