He previously served as the chair of the board of directors at Metra, the Chicago commuter rail system.

[9][12][13] At the age of 13, Martin Oberman was appointed as a page in the United States House of Representatives.

[6] After nearly three years (1969–1972) as a lawyer with the Chicago firm of Leibman, Williams, Bennett, Baird, and Minow,[citation needed] Oberman became General Counsel to the Illinois Racing Board under Anthony Scariano.

Oberman investigated and prosecuted various corrupt racing interests in License revocation proceedings for political payoffs, race-fixing and horse drugging.

[citation needed] Oberman, along with fellow independent alderman Dick Simpson, was one of only two aldermen to vote against the resolution appointing Michael Anthony Bilandic to hold the mayoralty after Richard J. Daley's death in office.

[18] On February 11, 2014, the board unanimously voted to make him Metra chairman, a position he held until November 1, 2016.

[21] [1] On July 5, 2018, President Donald Trump announced he was seeking to appoint Oberman to the Democratic vacancy on the United States Surface Transportation Board.

Following Joe Biden's inauguration as president in 2021, Oberman was chosen to serve as chair of the STB.