Irving A. Hadley was a successful Boston lawyer and it was expected that his son would follow him in the profession.

[1] Hadley attended Lynn English High School, where earned letters in baseball, basketball, track, rowing, and football.

Hadley started out as Mercersburg's third baseman, but moved to the mound after the team's pitcher dropped out of school.

On June 4, 1924, Hadley threw a perfect game against the State Forestry School in which he struck out 26 of 27 batters he retired.

He left the school during his sophomore year after being ruled academically ineligible for the upcoming baseball season and signed with East Douglas in the independent Blackstone Valley League, where he went 17–2.

[1] That season, Yankees manager Joe McCarthy offered Tony Lazzeri to the Senators for Hadley and infielder Jackie Hayes.

Instead, Hadley was traded to the Chicago White Sox after the season with Hayes and Sad Sam Jones for John Kerr and Carl Reynolds.

[1] After making three appearances for the White Sox, Hadley was traded to the St. Louis Browns for Red Kress.

Hadley finished the 1932 season as the American League leader in losses (21), earned runs allowed (149), walks (171), and hit batters (8).

[1] On January 17, 1936, Washington traded Hadley and Roy Johnson to the Yankees for Jimmie DeShong and Jess Hill.

[1] In Game 3 of the 1936 World Series, Hadley gave up 11 hits, but only one run in a 2–1 victory over the New York Giants.

According to Shirley Povich of the Washington Post the move was made because "Hadley is on the payroll of the American League publicity department as exhibiting for its official movie film, and the National League would scarcely permit one of its pitchers to promote good-will for the AL".

In 1942, he played for a Lynn semipro team and pitched a four-hit shutout against the Boston Braves in an exhibition game benefiting the war-effort.

[12] He later worked as a paint salesman, represented a fuel oil company, and sold office equipment.