Headrick grew up in Fort Worth, Texas, where he was an All-District fullback at North Side High School.

[1][2] While working in the west Texas and New Mexico oil fields during the off-season, in 1960 he became one of the first players to sign with the Dallas Texans in 1960 as an undrafted free agent.

In his first year with the Texans, Headrick set the standard for playing hurt, after fracturing a vertebra in his neck in a pre-game collision at Houston.

In his book "The American Football League – A Year-by-Year History, 1960–1969", Ed Gruver quotes Texans/Chiefs coach Hank Stram as saying that Headrick, who refused to wear hip pads, had the highest pain threshold [he'd] ever seen in an athlete.

"He was a fantastic football player", former Chiefs tight end Fred Arbanas told The Kansas City Star.

He earned the rank of Diamond Life Master awarded by the American Contract Bridge League.