[3] He graduated from Butte High School in 1972 and, intending to become a TV news presenter, enrolled at University of Montana to study journalism.

Thus, when a seat in the Montana House opened up in the Silver Bow County-based 83rd District in 1976, Cooney decided to run.

He later admitted that his family name may have helped him and quipped that when he was campaigning on the doorstep, some people thought he was collecting for the local paper.

[3] Cooney said that he thought Lynch would be able to offer "a little more diplomacy" with the Montana Senate, which was evenly divided between Democrats and Republicans.

[10] In 1979, Cooney received his Bachelor of Science from the University of Montana[11] and in that December, he married DeeAnn Gribble after five years of dating.

[3] The Cooneys moved to Washington, D.C. in 1982 so that DeeAnn could attend Antioch School of Law and Mike transferred to Baucus' staff there.

[3] Cooney was unopposed in the Democratic primary and defeated the Republican nominee, State Senator Pete Story, by 174,917 votes (49.28%) to 163,830 (46.16%).

[12] His victory was considered an upset as he was outspent by his opponent and Republicans had won the open gubernatorial seat, incumbent Democratic U.S.

Senator John Melcher was defeated by Republican Conrad Burns and George H. W. Bush carried the state's four electoral votes in the presidential election.

[13] Cooney succeeded two-term Republican Jim Waltermire in the office, who had been running for Governor of Montana in the 1988 election when he was killed in a plane crash on April 8, 1988, after returning from a campaign event.

He names his greatest achievement as secretary of state in persuading the Legislature to let the office be run more like a business and having it funded entirely from fees paid for its services rather than through taxes.

[3] In February 2000, he announced six-term state representative Diana Wyatt of Great Falls as his running mate,[17] calling her "a woman of vision, courage and commitment".

[18] Cooney campaigned on three main goals: long-term economic development, encouraging businesses to stay in Montana and attracting new ones by working with them to develop and implement creative strategies; making education a higher priority through increased funding, giving a $3,000 bonus to teachers who become nationally board certified, creating a teacher-to-teacher mentoring programme, and increasing opportunities for technology and tribal colleges; and protecting Montana's environmental heritage by increasing funding for scientific research, protecting roadless land, working with loggers and conservationists to create forest stewardship programmes, and placing a moratorium on new game farms until more scientific research was done.

In 2008, he used his position as Senate President to argue forcefully for the Legislature to update the state's anti-discrimination laws to make it illegal to fire or discriminate against someone at the workplace just because they are gay, lesbian, bisexual or transgender.

[32] In 2015, he was promoted to become the Deputy Commissioner of the Montana Department of Labor and Industry, a job he performed until his selection as lieutenant governor.

Cooney's predecessor in the Lieutenant Governor's office was Angela McLean, who was appointed to the position in February 2014 following John Walsh's departure for the United States Senate.

Coincidentally, Bullock had appointed Cooney's wife DeeAnn to replace retiring judge Jeffrey Sherlock in the state's 1st Judicial District in Helena earlier that month.