He later worked as the head pro at golf clubs in California and Oregon, and competed on the Senior PGA Tour.

McCallister played for the University of Southern California golf team as an amateur, receiving All-American honors from 1956 to 1958, and becoming the first player to win the Pac-8 Conference and Southern California Intercollegiate Athletic Conference titles in consecutive years.

[1] The McCallister family moved to Corona, California,[2] and joined the San Gabriel Country Club.

He only started playing full-time on the tour one year later, after serving in the U.S. Army and being stationed at Fort Ord in Monterey Bay.

[1] He won the first title of his professional career at the 1960 Paul Bunyan Open, held at the Penobscot Valley Golf Club in Orono, Maine.

[7][3] He subsequently tied for third in attempting to defend his Orange County Open title, coming two shots short of a playoff between Bob Rosburg and Lema (the eventual winner) after three-putting on the last hole.

[3][8] That same year, he partnered with Major League Baseball player Albie Pearson to win the Bing Crosby Pro-Am.

[3] In the latter, he beat Bud Holscher to the $15,000 first prize, which was the richest sectional event by the Professional Golfers' Association of America at the time.

[10] McCallister won the 1967 Maracaibo Open Invitational by defeating Wes Ellis in a playoff,[3] after the latter tied the score on the final hole of normal play.