Sabo was born in Crosby, North Dakota, the son of Norwegian immigrant parents.

[1] When eight-term incumbent and fellow Democratic–Farmer–Labor Party (DFL) member Donald M. Fraser stepped down to run for the U.S. Senate, Sabo became the DFL candidate to succeed him in what had become the most reliably Democratic district in Minnesota (Fraser had defeated a 10-term Republican in 1962 and hadn't faced serious opposition since).

He endorsed his longtime chief of staff Mike Erlandson in the DFL primary—the real contest in this district.

Erlandson lost to State Representative Keith Ellison, also a progressive DFLer, who in turn won the general election and succeeded Sabo on January 4, 2007.

[9] U.S Senator Amy Klobuchar called Sabo a "friend and mentor," and Governor Mark Dayton praised him as "a great political leader and an outstanding public servant.