In 2014 he received a narrow plurality in his race for reelection, but did not attain the 50% threshold mandated by the Constitution of Vermont.

[2] The legislature almost always selects the candidate who received a plurality; this held true, and the General Assembly re-elected Shumlin to a third term by a vote of 110–69 in January 2015.

[4] He signed laws on physician-assisted suicide as well as the United States' first genetically modified food labeling requirement during his tenure as governor.

[7][10][11][12][13] Shumlin was appointed by Governor Madeleine M. Kunin to fill a vacancy in the Vermont House of Representatives.

[17] In 2002, Shumlin won the Democratic nomination for lieutenant governor, and lost the general election to Republican Brian Dubie of Essex in a three-way race that included Progressive Anthony Pollina of Middlesex.

[19] In 2006, Shumlin ran successfully for his old seat in the State Senate upon the retirement of Rod Gander, who served from 2003 to 2007.

The Party had promised not to play a "spoiler" role in the election if he supported single-payer health care, which he did.

[41] The defining event of Shumlin's first term was Tropical Storm Irene, which caused almost every river and stream in the state to flood, resulting in at least three deaths and one missing.

[42][43] The storm decimated multiple sections of U.S. Route 4 between Rutland and Quechee, making east/west travel through the southern part of state nearly impossible.

However, on January 19, 2012, Judge J. Garvan Murtha of United States District Court in Brattleboro ruled that the state of Vermont could not force Vermont Yankee to close down, as the legislation that attempted to do so was based on radiological safety arguments that are the exclusive concern of the NRC.

The judge also held that the state cannot force the plant's owner, Entergy, to sell electricity from the reactor to in-state utilities at reduced rates as a condition of continued operation.

[58][59][60][61] While the bill also allows private insurers to operate in the state indefinitely[62] In January 2014, Shumlin said he was fully committed to full implementation of single-payer health care, starting in 2017.

[65][66] In December 2014, Shumlin announced that he would abandon plans for single-payer health care in Vermont, citing "potential economic disruption".

He framed the challenge of opiate abuse as greater in scope than the recovery from Tropical Storm Irene.

[76] Shumlin said that the screening process weeded out people "who should not be accepted" and criticized governors who attempted to stop relocation, saying: "The governors who are taking those actions are stomping on the qualities that make America great, which is reaching out to folks when they're in trouble and offering them help, not hurting them.

[78] Most of these were issued in January 2017, when Shumlin (in one of his final official acts as governor) granted a pardon to 192 people convicted of misdemeanor marijuana possession in Vermont.

[81] In 2011, Shumlin expressed his support for "Team Kale" in its trademark dispute with fast food restaurant Chick-fil-A and said it sends the message "Don't mess with Vermont.