He attended the public schools of Wood River, Meeteetse, and Cody. In 1921, he graduated from the University of Wyoming at Laramie in Albany County. From 1921 to 1925, he attended Harvard University Law School.
During World War I, served as a second lieutenant in the infantry, United States Army. He was admitted to the bar in 1926 and practiced law in Cody until 1955 when he became governor of Wyoming. Milward ran for the Senate against Joseph C. O"Mahoney in 1940, but was defeated 58.7% to 41.3%. was narrowly elected governor in November 1954.
He defeated the Democrat William Jack, 56,275 (505 percent) to 55,163 (495 percent). was unseated after a single term in 1958, a heavily Democratic year nationally, after a single term in office by John Jay Hickey of Rawlins in Carbon County, 55,070 (489 percent) to 52,488 (466 percent).
He resumed his law practice in 1959. lived in Cody until his death in 1993 at the age of ninety-five. Along with Barry Goldwater of Arizona, Norris Cotton of New Hampshire, Bourke B. Hickenlooper of Iowa, Edwin Mechem of New Mexico, and John Tower of Texas, was one of six Republican senators who voted against the Civil Rights Acting of 1964.
However, as governor he had signed into law Wyoming civil rights measure in 1957 which had abolished racial segregation in his state. Alan was the Senate Republican Whip during the early 1990s.
An older son, Peter K., is a retired historian and administrator at the University of Wyoming who served in the state House from 1981 to 1984 from Sheridan County, where he was then residing while serving as an administrator at Sheridan College.
Mead still holds the office of governor. As a young man, Milward played professional baseball in Cody. One of his teammates was the subsequent Lieutenant Governor and Education Superintendent Bill Dodd of Louisiana.
They became close friends.
While a student at UW, he was both an athlete and a member of the university"s debate team Simpson served as a member of the Wyoming House of Representatives from 1926 to 1927. He was a member of the board of trustees of the University of Wyoming in 1939 and president of the board from 1943 to 1954.
He was a member of the National Association of Governing Boards of State Universities and Allied Institutions and served as president of the body from 1952 to 1953.
Milward Simpson"s grandson, Colin M. Simpson, is a former member of the Wyoming House from Cody who lost a Republican primary for governor in 2010 to Matt Mead of Jackson, a grandson of Clifford Hansen.