Castleman originally intended to breed My Charmer to Jacinto but that stallion's book was full so Seth Hancock of Claiborne Farm recommended the mare be bred instead to Bold Reasoning, a first-crop sire who had won the Jersey Derby and Withers Stakes in 1971.

Karen felt that the pronunciation of slough — a slow-moving channel of the Pacific Northwest — would be too hard for people to remember, so the spelling was changed to Slew.

[2] Seattle Slew's owners sent the colt to Billy Turner, a friend and former steeplechase rider who had trained horses seasonally in Maryland since the early 1960s.

Based at Belmont Park in the mid-1970s, Turner accepted Seattle Slew and another Taylor-Hill purchase and sent them to Andor Farm in Monkton, where his wife at the time, Paula, taught yearlings to be ridden.

"[8] Seattle Slew's debut was delayed by his initial awkwardness, but he started to attract attention over the course of the summer at Saratoga with some fast workouts.

[12] On October 16, Taylor stepped the colt up in class to enter the Grade I Champagne Stakes, then the most important race for two-year-olds in the United States.

His biggest rival was For the Moment, who had won four straight races including the Belmont Futurity and was a full-brother to champion Honest Pleasure.

His owners considered entering him in the Gotham Stakes on April 9 but Turner was against it because heavy rains had rendered the main track unusable, meaning the colt had not been able to properly work out.

"[16] The "Slew Crew" then relocated to Churchill Downs where the Taylors set up a camper opposite the colt's stall in Barn 42, which traditionally houses the favorite for the Kentucky Derby.

[19] Seattle Slew was the heavy favorite at odds of 1:2 but still faced a large field as many felt the colt would be vulnerable at the Derby's distance of 1+1⁄4 miles.

The two colts then dueled around the first turn before Cruguet got Seattle Slew to relax down the backstretch, under a tight restraint, allowing For the Moment to open up a lead of a length.

Other highly rated contenders were J. O. Tobin, the English champion two-year-old colt of 1976, and Iron Constitution, who had won the Withers Stakes.

[21] For the first time, Turner chose to have the colt given butazolidin before the race, fearing that Seattle Slew might suffer a minor injury in his final workout.

As expected, the two battled for the early lead, sprinting nearly ten lengths clear of the rest of the field while setting fast fractions of 22+3⁄5 seconds for the first quarter-mile and 45+3⁄5 for the first half.

Turner arrived late at the saddling enclosure, due in part to the number of cars parked on the backstretch, as well as his desire to limit the colt's exposure to the enthusiastic crowd.

[23][25][26] Cruguet stood up in the stirrups and raised his right hand triumphantly some 20 yards before the finish line, leading some to criticize him for the "emotional flourish".

"[8] After the Triple Crown, Seattle Slew was sent to Hollywood Park Racetrack, which increased the purse for the Swaps Stakes to over $300,000 to lure him to run on July 3.

Seattle Slew, boxed in for much of the race with Text to his side, eventually broke free but tired badly in the stretch.

[30] Despite the disappointing end to the season, Seattle Slew was the easy winner in the voting for champion three-year-old at the annual Eclipse Awards.

[31] In early 1978, Seattle Slew was stabled at Hialeah and was expected to make three or four starts in Florida, followed by a full campaign in New York's major stakes races.

Over an extremely muddy track, he settled in second place behind Gallant Bob for the first quarter-mile, then started to open up on the field, eventually winning by 8+1⁄4 lengths.

[38] Seattle Slew was being pointed to the Metropolitan Handicap at the end of May but suffered another setback when a filling in his left hind leg was discovered.

[40] In preparation for his fall campaign, Seattle Slew was sent to the Meadowlands on September 5 for a night race, the Paterson Handicap at a distance of 1+1⁄8 miles.

"[42] Two weeks later, Seattle Slew was entered in the Woodward Stakes, then held at Belmont Park over the American classic distance of 1+1⁄4 miles.

[45] In October, Seattle Slew and Affirmed met again in the 1+1⁄2-mile Jockey Club Gold Cup at Belmont, which was televised nationally on the CBS network.

Seattle Slew ran in fractions of 22+3⁄5 for the first quarter, 45+1⁄5 for the half and 1:09+2⁄5 for three-quarters – extremely fast early times for a long race.

This stretch run is still remembered as among the all-time best, ranking with Sunday Silence and Easy Goer's Preakness in 1989 and the battles between Affirmed and Alydar.

He is part of a unique three generation sequence of Belmont Stakes Winners: Seattle Slew (who won the race in 1977) sired A.P.

In 2006, Lava Man became the first horse to win the Santa Anita Handicap, Hollywood Gold Cup and Pacific Classic Stakes in the same year.

[4] In 2015, the state of Kentucky starting issuing a license plate bearing Seattle Slew's image, based on a photograph by Tony Leonard.