When Giorgio Chinaglia, who has died aged 65 after suffering a heart attack, was asked if it was true that he had played with Pelé, the Italian striker is said to have replied: "No, Pelé played with me" – which tells you all you need to know. A man of the football world who was revered on two continents, Chinaglia was also a self-centred, colourful and uncompromising maverick who had little regard for convention or authority either on or off the field. "If you don't have an ego, especially in sports, you're not going to go very far," he said in 2006.
He certainly had an ego, and he did go far – from his birthplace in Carrara, Tuscany, via south Wales to success at club and international level back in Italy. At the height of his career he moved to the North American Soccer League (NASL), playing for the New York Cosmos alongside Pelé and Franz Beckenbauer iand considering himself every bit their equal.
A physical and committed striker rather than a player of natural talent, he nevertheless scored goals wherever he played, and was held in especially high regard at Lazio after inspiring them to their first league title – although teammates and coaches were not always so enthusiastic.
Chinaglia moved to Cardiff in 1955 at the age of eight when his father Mario was looking for work in the steel industry. Giorgio heeded Mario's advice not to take up rugby, and when he was 13 scored a hat-trick for Cardiff Schools that earned him a contract with Swansea Town, now Swansea City.
They were then in division three, but Chinaglia hardly wrote his name in lights. He was often frustrated by the menial tasks expected of him, and although he made his league debut in February 1965, he was given a free transfer little more than a year later, as much for his casual attitude to training and timekeeping and interests in drinking, gambling and women as for any lack of ability.
He returned to Italy to complete his military service, which meant joining a regiment for footballers. Compulsory training and military discipline improved his game and although he was ineligible for Serie A for three years because he had played professionally outside Italy, he was able to join Massese of Serie C, near the town of his birth, and then Internapoli at the same level, where he scored 26 goals in 66 games over two seasons (1967-69).
Lazio gave him his chance in Serie A and although he was more effective than elegant, he eventually went on to score 98 goals for them in 209 appearances. He became the darling of their fans, who nicknamed him Long John for his resemblance to John Charles, the Wales striker who had starred in Italy a generation before. For them he could do no wrong, especially when he taunted Roma supporters after scoring against them in the derby, and despite his rivalry with teammate Gigi Martini. They were rewarded in 1974 when Chinaglia led Lazio to their first ever Scudetto – the right to wear the tricolour badge – scoring 24 goals, including the championship-winning penalty against Foggia.
He was also a fixture in the Italy squad, having set up the goal for Fabio Capello that beat England at Wembley in a vital World Cup qualifying match in 1973. However, his fiery temper ended his international career. After being substituted in a game against Haiti in the 1974 World Cup finals, he argued with the head coach and stormed away, kicking down the dressing-room door and smashing water bottles in rage.
Then in 1976 came the audacious decision to leave Italy for the nascent NASL, partly at the behest of his American wife, Connie, and partly, according to some, because Lazio could no longer afford his wages, and after the Italy incident were relieved to be rid of a ticking time-bomb. But whereas many big names took the dollars on offer in order to prolong careers that were on the wane in the more demanding European theatre, Chinaglia was a great player in his prime, and his arrival at the Cosmos a year after that of Pelé gave the credibility of the league a significant boost.
Headstrong and full of self-belief, he was no respecter of reputations, even Pelé's. He once criticised the great Brazilian's fitness, which led to boos from some fans, demanded better service from his illustrious teammate, and responded to Pelé's criticism of his positioning with: "I am Chinaglia. If I shoot from a place, it's because Chinaglia can score from there."
Coaches and team officials found him difficult, but he enjoyed the patronage of Warner Communications boss Steve Ross, and the city's press were grateful for his presence. "I remember him holding court after games in the locker room wearing a brocaded dressing gown," the veteran analyst Tony Kornheiser said. "He understood what it was to be a star."
He was the league's top scorer on four occasions, won the MVP (most valuable player) award in 1981 and ended up as the NASL's all-time leading scorer with 262 goals. He was inducted into the USA's National Soccer Hall of Fame in 2000.
Off the field, he found New York very much to his liking, and he became an American citizen in 1979, but was tempted back to Italy in 1983 to become president of Lazio. It proved an unwise move – the club was heavily in debt, and while his abrasive character could be excused in a player, it did not play well in a president. He was banned for eight months for threatening a referee.
Worse was to follow when he was investigated by police over the possible involvement of organised crime in an attempt he made to buy Lazio. But he answered his critics in a distinctive American-Italian accent: "I don't give a s**t. Why don't people judge me for what I did on the field?"
He is survived by his second wife, Angela; by their two sons; and by the son and two daughters from his marriage to Connie, which ended in divorce.
• Giorgio Chinaglia, footballer, born 24 January 1947; died 1 April 2012