Although he played at the relatively obscure position of left guard on the offensive line, Tom Mack gained a lion's share of attention during his 13 star-studded seasons with the Los Angeles Rams from 1966 through 1978. He never missed a game during his 184-game tenure, a consecutive game streak third in Rams' history behind only Jack Youngblood and Merlin Olsen. During the years that Mack played, the Rams enjoyed 12 winning seasons in 13 and compiled a .720 won-lost record (129-48-7). They won their division eight times and wound up in four NFC championship games. The Los Angeles team was loaded with outstanding talent but Mack, as the youthful leader of an excellent offensive line, was one of the most honored of all Rams.

The 6-3, 250-pound Mack earned the first of 11 Pro Bowl invitations after his second season in 1967. From that year through his final 1978 campaign, Tom missed earning a Pro Bowl spot only following the 1976 season. At the time of his retirement, his 11 Pro Bowl games ranked him in a third-place tie with Bob Lilly and Ken Houston among those with the most appearances in the post-season classic. Olsen ranked first with 14 Pro Bowl appearances and is followed by Jim Otto with 12. Mack was also all-pro or All-NFC nine times in a ten-year span from 1969 through 1978. As was the case with the Pro Bowl invitation, he missed All-NFC acclaim only in 1976.

An All-America at Michigan in 1965, Mack was the No. 1 pick of the Rams in the 1966 NFL draft. Tom, who was born in Cleveland, Ohio, on November 1, 1943, was one of only two rookies to survive the entire season on George Allen's veteran-dominated squad. Tom got a starting chance in the fifth game when starter Don Chuy was injured. Mack moved into the lineup the next three games, then relinquished the role briefly to Ted Karras before grabbing the starter's job again. He remained the Rams' starting left guard for the next 12 years.