In the 1960 American Football League Championship Game, he caught four passes for 71 yards as the Oilers prevailed 24–16 to win the inaugural AFL title over the Los Angeles Chargers.

After a promising rookie season, in 1961, he started all 14 games and established himself as a superstar in the AFL by setting a single-season record with 1,746 yards receiving along with 12 touchdowns.

One of quarterback George Blanda’s main targets, Hennigan was the second professional football player to catch more than a hundred passes in a single season (101 in 1964, an AFL record) and to twice gain over 1,500 yards receiving (1961 and 1964).

Hennigan had the All-time AFL single game record of 272 yards receiving, against the Boston Patriots on October 13, 1961.

The 13 passes caught in the game is tied for the most ever in the AFL, shared with Lance Alworth, Lionel Taylor, and Sid Blanks.

In the 1961 American Football League Championship Game, he had five catches for 43 yards as the Oilers prevailed for their second and final AFL title.

[6] Hennigan operated an educational tutoring service in Shreveport and worked with prisoners seeking the General Equivalency Diploma (GED).