As an administrator, he served as secretary, vice-chairman and president of the Meath County Board and was instrumental in organising a prototype International Compromise Rules Series in 1968.
After a period playing with Ardcath in the Fingal League, he subsequently lined out with Rathfeigh and captained the team to the County Minor Championship title in 1936.
Four years later the Donaghmore club secured the County Senior Championship title when a team, captained by McDermott, beat Skryne by 1-08 to 0-02 in the 1942 final.
McDermott, who played well in the drawn match but had, by his own admission, "a poor game in the replay" and was not among the members of the junior panel who were subsequently invited onto the senior team.
After surrendering the title the following year, McDermott claimed his third provincial winners' medal after scoring two goals in the 4-05 to 0-06 defeat of Westmeath in the 1949 Leinster final.
He was once again selected at left corner-forward for the 1949 All-Ireland final against cavan and claimed his first winners' medal after the 1-10 to 1-06 victory in what was Meath's inaugural championship title.
In the final against Offaly he came on as a substitute for the injured team captain Tom Duff, scored two goals and collected his sixth winners' medal after the 4-07 to 2-10 victory.