With the arrival of the Canadian Pacific Railway in 1882, Moosomin was established as the first Saskatchewan community on "steel".

He founded the R. D. McNaughton Company, a general store operation that played a vital role in early settlement.

These included the 16th Light Horse, in the early 1900s (decade); 10th Regiment, Canadian Mounted Rifles, 1915; 217th Battalion, CEF, and the 101st Battery of the 22nd Field Regiment which was based at Moosomin Armories (presently the Community Hall).

In the interwar years he was Chairman of the National Research Council and following the Second World War was Chairman of the International Joint Commission which handled questions pertaining to the international waters along the Canada-United States border.

[5] The social life of the early settlers of the area was limited by distances and transportation methods.

July 1 in Moosomin was the highlight of the summer for many years, there would be a parade, sports events and refreshments.

[5] Moosomin grew significantly in the late 1960s and early 1970s with the construction of a major potash mine 35 kilometres (22 mi) to the north.

The PotashCorp Rocanville potash mine just north of the community is undergoing a $2.8 billion expansion, the $60 million Red Lily Wind Farm just west of the community started producing power in February 2011, since the Trans-Canada Highway was twinned through Moosomin in November 2009 several new businesses have been established along the highway, the Southeast Integrated Care Centre has become a major health care centre for a large region of south-eastern Saskatchewan and south-western Manitoba, and there has been significant activity in the local oil patch, which is at the northern end of the Bakken Formation.