Both sets of Owen's ancestors had moved to the South Wales Valleys in search of work with increased steel, iron and coal production attracting workers from all over Britain.

[9][10] Broadbent describes how, by age ten, Owen developed "some rudimentary ring craft and already had the boundless energy that would be his signature ... His punches were light but his effort huge.

[14] Owen attended Georgetown Secondary Modern School until the age of 16 when he left to take up a role as a machine operator in a local Suko nuts and bolts manufacturing factory.

[15] His exertions in the factory, coupled with his frequent runs in the hills of the South Wales Valleys with his brother Kelvin, led Owen to develop renowned levels of speed and stamina.

A septic finger injury led to a lacklustre defeat to George Sutton in the 1975 Welsh Amateur Boxing Association (ABA) Championships after Owen refused to pull out of the fight.

[16][18] Owen's father Dick later stated that an official from the Welsh ABA approached him after the fight and confessed how the organisation had been under pressure to ensure O'Sullivan's victory in order for him to be selected for the 1974 British Commonwealth Games in New Zealand.

After defeating John Raeside in the second round during their bout in Pontypool, he was described as reducing his opponent "to helplessness with a non-stop two-fisted assault" and was chosen as the most impressive fighter in the two teams on the night.

[18][20] Owen became well-known for his seemingly small, thin frame as he grew older; he was chosen to represent Wales in a contest against Sweden in February 1975 and was greeted with jeers and laughter when he removed his robe.

His physique attracted further attention in November 1975; while representing Wales against an army team, a doctor initially refused to pass him fit to fight believing him to be too frail to box.

The card suffered several interruptions: there were angry outbursts when British soldiers entered the arena, a bomb threat was phoned in against the site and, during Owen's bout, the lights failed for several minutes.

[27] It was from his Welsh title win that Owen gained another of his nicknames, the "Bionic Bantam", after a reporter for the Western Mail likened him to Steve Austin from The Six Million Dollar Man.

[30] When the offer of a British title fight with Maguire failed to materialise, Owen instead fought debutant fighter Terry Hanna at Ebbw Vale Leisure Centre in June 1977, defeating him with a fourth-round knockout.

[31] Further disappointment followed as Maguire took a fight against Franco Zurlo in September of the same year,[32] leaving Owen with an offer of a second rematch against George Sutton on only three days' notice.

The fight took place at Midland Social Club in Solihull and Sutton proved a sterner test than most had anticipated in the early rounds, landing a strong punch to Owen's jaw that wobbled him.

[33] Maguire was entering the fight on a three-fight losing streak, having suffered defeats to Heleno Ferreira and Alberto Sandoval before unsuccessfully challenging Zurlo for the European bantamweight championship,[32] and Owen was expected to be a serious threat to the Irishman's two-year reign.

A month later, Owen fought Antonio Medina at Marton Country Club near Newcastle and was surprised early on when his opponent emerged as a southpaw, the first time he had faced a fighter using the stance in his career.

[45] Australian Paul Ferreri, who had lost the belt to Shittu in January 1977,[46] stated his willingness to contest the vacant Commonwealth title with Owen, offering the Welshman £4,000,[47] on the stipulation that the fight be held in his home country.

At the weigh-in, Owen was marginally overweight, prompting a last minute training session involving running up and down the hotel stairs until he hit the 118 pounds (54 kg) limit.

The British Boxing Board of Control's (BBBofC) representative at the fight, Harry Vines, attempted to approach Owen's team to find out what was causing commotion and found himself being pushed and shoved by members of the crowd before Spanish police ordered him to return to his seat.

[56] At the start of the tenth round, Owen returned to the middle of the ring but was forced to wait as Rodríguez took several extra minutes to leave his corner before standing to taunt his opponent in front of the home crowd.

[61] Owen was eager to impress in the fight as victory would also see him achieve a lifelong ambition of retaining a Lonsdale Belt, which became the permanent property of a fighter once they had completed three successful defences.

When Owen and his team arrived at Ebbw Vale Leisure Centre for the bout they found that Vega had pulled out of the contest without warning and the American promoters instead offered a replacement, Jose Garcia.

[64] Owen ended 1979 with one further victory over American David Vasquez, a fighter who had unsuccessfully challenged world champion Lupe Pintor a year earlier and had been in line to meet Wilfredo Gómez.

Rodríguez was short of competitors willing to fight in his home country and was forced to accept the Ebbw Vale Leisure Centre to secure a large prize fund.

[73] Pintor had edged a highly controversial split decision over stablemate and long-time champion Carlos Zárate to win his world bantamweight title in June 1978.

[78] Owen was considered the underdog with odds on his victory being offered at 6–1 before the fight,[79] but he surprised many in the opening round by actively pursuing Pintor around the ring, seeking to engage with the champion.

[82] Pintor began to fight more aggressively in the ninth round and his approach paid off when he caught Owen with a punch that knocked the Welshman down for the first time in his professional career.

[79] Owen's death, along with those of Kim Deuk-koo and Francisco Bejines in the early 1980s, ultimately led to boxing title fights being fought over 12 instead of 15 rounds in an attempt to improve the safety of fighters.

[106][107] Historian Martin Johnes has argued that Owen was an "emblematic figure who represented both the ideals of Welsh working-class communities and their suffering and courage in the face of adversity and tragedy".

He noted that Owen's funeral resembled those of the victims of coal mining pit disasters which had frequented the area while the Western Mail described him as "the latest hero of a town scarred by bitter memories".