1972: two-year-old season Boldboy showed promise as a two-year-old but also showed serious temperamental problems. Hern said that he was a "very, very difficult" horse to train.
1973: three-year-old season Although he could not contest the
2000 Guineas itself, Boldboy began his second season in April in the
Greenham Stakes, one of the major trials for the Newmarket
classic. Ridden by
Joe Mercer he started a
16/1 outsider but won by length from the undefeated Dewhurst Stakes winner
Lunchtime, who had been the ante-post favourite for the Guineas.
Mon Fils, who finished a length behind Lunchtime in third went on to boost the form by recording a 50/1 upset win in the 2000 Guineas. Later that month Boldboy was moved up in distance for the
Blue Riband Trial Stakes over eight and a half furlongs at Epsom and finished second to Gospill Hill when carrying seven pounds more than the winner. The gelding was then sent to France for the
Prix de la Porte Maillot over 1400 metres at
Longchamp Racecourse in June. He started at odds of 7.9/1, took the lead on the turn into the straight and won by three lengths from the Italian-trained Brook. Boldboy returned to France for the Group One
Prix Jacques Le Marois at
Deauville Racecourse in August and finished fourth behind
Kalamoun, Rose Laurel and
Sparkler, three and a half lengths behind the winner. In autumn, Boldboy raced in England again and was brought back in distance to compete over sprint distances. In the Diadem Stakes over six furlongs at
Ascot he led from the start and won by half a length from the
Cork and Orrery Stakes winner Balliol, before going on to win the Challenge Stakes over the same distance at Newmarket at odds of 8/13.
1975: five-year-old season Boldboy had his least successful season as a five-year-old in 1975 when he failed to win in seven races. His best efforts came when finishing fourth in the Prix de la Porte Maillot, second to Son of Silver in
Prix Messidor and third to Imperial March in the
Queen Anne Stakes (then a Group Three race open to three-year-olds and up) at
Royal Ascot. During this season, Boldboy began to race in
blinkers.
1976: six-year-old season On his debut as a six-year-old, Boldboy recorded his first success in over a year when he won the Abernant Stakes for a second time, beating Honeyblest by a head after leading from the start. He ran poorly when unplaced in the Lockinge Stakes but then finished third behind Ardoon and Record Token in the Queen Anne Stakes and fourth, beaten less than half a length in a blanket finish for the Prix de la Porte Maillot. The gelding was then dropped into
handicap company for the Joe Coral Handicap at
Haydock Park and finished second to Berkeley Square, to whom he was conceding thirteen pounds. He produced one of his best performances in defeat in the
Waterford Crystal Mile at Goodwood in August, when he was beaten a short head by Free State, carrying nineteen pound more than the runner-up. Two weeks later, Boldboy, again conceding weight to his opponents, won the Sanyo Stakes over seven furlongs at
Doncaster Racecourse and won by a length and a half from the four-year-old filly Be Tuneful. In his last two starts he finished fourth to Honeyblest in the Diadem Stakes and third to Star Bird and Be Tuneful in the Challenge Stakes. During his 1976 campaign, Boldboy broke the record for earnings by a British-trained gelding, surpassing the mark set by the stayer
Petty Officer who had been retired a year earlier. He held the record until
Bedtime finished runner-up in the 1984
Japan Cup.
1977: seven-year-old season Boldboy (now racing without blinkers) had his most successful season as a seven-year-old in 1977, with
Willie Carson taking over as his regular jockey. He began with a third win in the Abernant Stakes and then finished second by a head when attempting to concede nine pounds to the four-year-old colt Duke Ellington in the Victoria Cup at
Kempton. In May he returned to sprinting for the Duke of York Stakes over six furlongs at
York Racecourse. He started at odds of 7/1 Boldboy won his three remaining races in 1977. In September, he won the Sanyo Stakes for a second time, beating the
Jersey Stakes winner Gwent by five lengths with the
1000 Guineas winner
Mrs McArdy a length and a half away in third. He had to work harder to win the Challenge Stakes for the second time at odds of 11/8
1979: nine-year-old season Boldboy made only two appearances in his final season. In April he attempted to win the Abernant Stakes for the fifth time, but finished second, four lengths behind the four-year-old Vaigly Great. In the following month he finished third behind
Formidable and
Roland Gardens in the Cold Shield Windows Trophy over one mile at Haydock. ==Retirement==