[1] Tillis challenged for the WBA world heavyweight title in 1981, but was defeated in a fifteen-round unanimous decision fight against Mike Weaver.

[2]) He holds notable wins over Ron Stander by TKO in the 7th round in 1980, and the hard punching Earnie Shavers by ten-round decision in 1982.

"Quick" was influenced to begin training to become a boxer after he listened to the 1964 bout between Muhammad Ali and Sonny Liston on the radio.

He enlisted the help of noted trainer Ed Duncan, by becoming involved in the sport at the O'Brien Park recreation center in north Tulsa.

He blew that momentum only a few months later, being upset by undefeated contender Pinklon Thomas, who was a late substitute, via an 8th-round knockout loss.

Having scored four wins, Tillis challenged future two-time world champion Tim Witherspoon in September 1983, for the vacant North American Boxing Federation title.

After the fight, Tillis' trainer Angelo Dundee left him and advised him to retire, as he had just suffered his third defeat in thirteen months.

After extensive medical examination, Tillis' strange recurrent fatigue midway through fights was found to derive from a severe allergy to the classic fighter's diet of milk and eggs.

A doctor provided Tillis with a more suitable diet, in the training for his upcoming fight with Mike Tyson, a red-hot prospect with a 19–0 (19 knockouts) record.

Being interviewed by the ABC Sports Network staff, Tyson himself said he just "fought a guy who was up for this fight, in the greatest shape in his life.

In 1987, he was upset in eight rounds, as underdog (and regular Tyson sparring partner) Michael Williams came off the floor to stop Tillis.

Tillis was brought in to fight reigning cruiserweight world champion Evander Holyfield, who was making a high-profile move into the heavyweight ranks.

However, his days even as a journeyman appeared over, as hard-hitting (and future WBO World Champion) Tommy Morrison stopped him out in one round.

[5] His daughter Iciss played basketball at Duke University as a center, and was on the United States National Team for the 2003 Pan American Games.

Tillis places the priorities in his life as "Serving The Lord Jesus Christ, Cowboy-ing and volunteering with amateur boxing clubs".

Bringing to fruition film adaptation of his autobiography, Thinkin Big: The Story of James Quick Tillis, the Fightin' Cowboy, is his pet project.