Prior to 1966 Van Moer played with Beveren. He went back to his first club after a spell at Beringen in the early 1980s. He played 57 times and scored 9 goals for the national team between 1966 and 1982, starting in a 1-0 friendly win against Switzerland on 22 October 1966. Van Moer was in the team for the 1970 and 1982 World Cups and for the Euro 1980 in which Belgium finished second.
Van Moer began with home town club (Beveren-Waas), then in the third tier of the Belgian League. A move to Royal Antwerp in 1965 was influenced not only by a chance to play in the 1st Division, but by the fact he was already working in that city as an electrician. At the end of '66 he won his first Golden Shoe Award, having won his first international cap earlier that year.
It was during his 3 years at Antwerp under the guidance of coach Harry Game, that Van Moer, against his wishes, was moved from a wide right role to central midfield, preparing him to eventually succeed to another of Belgium's most celebrated players Jef Jurion, in the national team.
Following relegation for Antwerp in 1968, a protracted move to Standard Liège ensued, Van Moer resisting the interest of 1. FC Köln to remain in Belgium, and also Club Brugge KV, with whom he had made a personal agreement. The 150,000 Euros fee for the now established international was at the time a Belgian record.
Wonderful domestic success followed at Standard, winning the championship in '69, '70 and '71 and making it a hat-trick of Golden Shoes by winning the award in both '69 and '70.
Internationally he was a regular too, appearing in the 1970 World Cup Finals and scoring twice in the only game his country won in Mexico, 3-0 vs. El Salvador. Van Moer also played a key role in helping his country qualify for the semi-finals of the European Championship two years later. After Belgium had defended stubbornly in a goalless quarter final, 1st leg in Italy, he scored the opening goal midway through the first-half in the return at Anderlecht's Parc Astrid. But then something was to happen, putting the Belgian’s career on hold. On the stroke of half-time, Bertini's lunge resulted in a broken leg for Van Moer, a bitter-sweet day for the home nation who ultimately celebrated a 2-1 victory.
Although he recovered, the leg-break and other injuries restricted his international appearances over the next 3 seasons. By October 1979, aged 34, without an appearance for The Red Devils for four and a half years, international football couldn't have been further from his thoughts. But wily Belgian coach Guy Thys had other ideas. Van Moer was an inspired choice for a Belgian side who had forgotten how to win, as they prepared to take on Portugal in a ‘do or die’ EC qualifier. Van Moer again came up trumps with the first goal in a 2-0 win. Van Moer also performed key roles in home and away victories over Scotland, which propelled Belgium to qualification for the Finals tournament in Italy.
Striker Horst Hrubesch may have scored two goals to secure final victory for West Germany, but for many the outstanding player of the tournament was the Belgian central midfielder with the seemingly boundless energy. He ran the show in most every game he played, scheming, prompting and holding the ball, never wasteful his performances were as dynamic as they were inspirational as Belgium went all the way to their only major Final. Van Moer was arguably the most influential player in the tournament and indeed at 35, his performances earned him 4th place (equalling the best ever showing by a Belgian) in the European Footballer of the Year poll. Karl-Heinz Rummenigge, Bernd Schuster and Michel Platini finished ahead of him.
Van Moer’s international career went on for another 2 two years, long enough to appear in another World Cup Finals series. Named captain in the absence of Eric Gerets, for the 2nd Phase game against Poland his international career ended when replaced by François Van der Elst at half-time. Belgium trailed by two at the interval and went on to lose 0-3, Poland's inspiration coming from Boniek who was the only player to score.
As for his club career, he had left Standard in 1976 and played for the Limburg first division team FC Beringen for a few seasons (he owned a café in the Limburg capital Hasselt). In 1980, after his career had been rekindled, he made a transfer to his original team SK Beveren (which had become Belgian champion in 1979). He stayed there for 2 more seasons and concluded his career in Limburg again at Sint-Truiden, where he became trainer-player.
After he stopped playing football, he became coach with Sint-Truiden, SK Beveren, Assent and FC Diest, before calling it a day, somewhat disappointed by the general professional level of the Belgian football players.
He was called by the Belgian Football Union to do some prospective work and became assistant coach to national coach Paul Van Himst in 1995 after a few heavy defeats of the Red Devils. He succeeded to Van Himst as a head coach in 1996 for 5 games.
However, people in the Football Union and the press were not very delighted by his lack of communicative skills and at the beginning of 1997, he was, in his turn, replaced by Georges Leekens. He has not taken up any managerial tasks since.