Widseth was born in Gonvick, Minnesota in 1910. He played high school football in McIntosh, Minnesota and began his college football career at the Northwest School of Agriculture (later renamed University of Minnesota, Crookston) where he graduated in 1932. Widseth next enrolled at the University of Minnesota where he played football for Bernie Bierman's great Golden Gophers teams of the mid-1930s. The Golden Gophers compiled a record of 23-1 during Widseth's three seasons on the team from 1934-1936. Widseth reportedly "'lived' in enemy backfields and was unquestionably the pillar of strength in the Gopher line" during a period in which they claimed three consecutive national championships. The only game the Golden Gophers lost during Widseth's three years as a starter was a 6-0 loss to Northwestern in 1936. Minnesota had a 28-game winning streak when they went to Evanston for a Halloween Day game against Northwestern. The game was scoreless when Widseth tackled a Northwestern player, and the referee accused Widseth of "slugging" the Northwestern player. After a 15-yard penalty was assessed, the ball was placed at Minnesota's one-yard line, and Northwestern scored a touchdown for the only points of the game.
Widseth also won two varsity letters as a pitcher and first baseman for the Minnesota baseball team.
Widseth was selected as a first-team All-American in all three seasons he played for the Golden Gophers. As a sophomore in 1934, he was selected as a first-team All-American by the International News Service ("INS") -- the Hearst newspaper syndicate. In 1935, he received first-team All-American honors from the United Press ("UP"), the All-America Board,Liberty Magazine, the INS, the North American Newspaper Alliance, the Central Press Association, and the Walter Camp Football Foundation ("WCFF"). In 1936, he was a consensus All-American receiving first-team honors from the Associated Press, the UP,Collier's Weekly, the INS, the Newspaper Editors Association,Liberty Magazine, the Central Press, and WCFF.
Widseth was drafted in the first round (fourth overall) of the 1937 NFL Draft. He played for the New York Giants from 1937-1940. Widseth was recognized as an all-NFL player three consecutive years. As a rookie in 1937, he was selected as a second-team All-NFL player by Collyers Eye Magazine, the INS, the NFL, the New York Daily News and the United Press. In 1938, he was rated a first-team All-NFL player by Collyer's Eye, the Pro Football Writers, the INS, the NFL, the New York Daily News, and the United Press. In 1939, he was selected as a second-team All-NFL player by the NFL and New York Daily News.
Widseth coached St. Thomas College from 1945 to 1946 and his team won the Minnesota College Conference title both years.
Widseth was inducted into the College Football Hall of Fame in 1954. His official biography at the Hall of Fame describes him as follows: "A slashing, driving invader, Widseth used his 6-2 220-pound body to pummel opposing players, relentlessly advancing until the ball-carrier was within his grasp and quickly felled."
↑Stuart Cameron (1935-11-29). "Grayson On U.P. All-American Team: MOSCRIP AND LUTZ PLACED ON RESERVES". Oakland Tribune.
↑Christy Walsh (1935-12-08). "Stars Listed on Official All-America Team". Salt Lake Tribune.
↑"Grayson on Honor Team: Liberty's All-Star Eleven Released; Moscrip and Duvall Placed". Los Angeles Times. 1936-01-02.
↑Davis Walsh (INS Sports Editor) (1935-12-05). "Walsh's National Eleven Leaves Ohio Out in Cold: Both Minnesota Tackles Chosen; Backfield Includes Smith, Berwanger, Wilson and Grayson". Circleville Herald.
↑"Four Coast Stars on All-America Elevens: Kerr, McGugin, Phelan and Dorais Select 1935 All-Star Teams; Moscrip, Grayson Named". Los Angeles Times. 1935-12-01.
↑Bill Braucher (1935-12-08). "SOUTH LEADS OTHER SECTIONS - ALL AMERICA: 54~Captains Select Central Press All-American Teams". Kingsport Times.