When my fellow Dutchman Louis van Gaal conducts his first pre-match briefing next week as manager of Manchester United, I have a pretty good idea of how he will approach it. I know because not only did we play together at Ajax when we were both barely out of our teens, but for seven years we shared a small office at the stadium during his glory years as Ajax coach. So, yes, when Man Utd line up on Wednesday for their friendly against LA Galaxy, I’ll be remembering those intense times.

Both of us started our footballing education in Amsterdam in the 1960s. I was from the west side of town but Louis grew up in the east of the city, in Galilei Park, in the heart of the Watergraafsmeer neighbourhood. The Watergraafsmeer is synonymous with Ajax football club, because in those days its little stadium lay in a park on the same stretch of reclaimed flatland. Nobody living in Watergraafsmeer at the time could have escaped the Sunday football ritual of fans eagerly making their way to the stadium, talking about the match, debating the line-up, camouflaging their love of the club with criticism. Every match day the noise, the light and the smell of Ajax hung over the Watergraafsmeer. I was a football-mad boy from across town, and I was jealous of the boys of Amsterdam-East and their club.

The young Louis van Gaal also fell under the spell of Ajax, even though his large family (he was one of nine children) was more connected to RKSV De Meer, a small neighbourhood amateur football club, whose Catholic roots reflected those of the Van Gaals. All the Van Gaal boys were members of RKSV De Meer, a club that differed in every way from the dominant and slightly vulgar, flashy, middle-class Ajax.

Louis played in Galilei Park and at all the neighbourhood spots where boys gathered to play football. He owned the ball they used in the street games, and he was good. Perhaps he was the best footballer of them all, although he looked gangling and was stubborn even then. One day, the ball tucked under his arm, young Louis crept into the unguarded Ajax stadium with a couple of friends, and began kicking around on that magical grass until a groundsman chased them away. But he had done it: he had played in the stadium.

In his teens, Louis started going along to watch Ajax’s training sessions. The club was then led by a remarkable man, Rinus Michels. Michels was a former Ajax centre-forward, who, after retiring, taught gymnastics in a school.

In 1965 Michels quit his teaching job to coach his old club. At training sessions, most of the watching boys stood and gaped at footballers such as Piet Keizer, Sjaak Swart and Tonny Pronk. Among them was a talented teenage rascal named Johan Cruyff. But Louis’ eyes were also on Michels, the coach: what the man did, how he did it, the training methods with which he was shaping what would become the world’s best club team. Even then, Louis – the future manager of the Dutch national team – was observing with a coach’s eye.

Meanwhile, the star of the Galilei Park was playing for the RKSV De Meer first team. He wasn’t a quick centre-forward, but he could score and head and read the game. He was a wonderful attacker, who took up positions cleverly, coupling intelligence with the technique learnt on the street. When he was 16, Ajax’s scouts tried to sign him, but his family insisted that he graduate from high school before committing to something as unpredictable as football. Even after graduation he began studying to be a gym teacher, only finally signing for Ajax when he was 18. It was a comparatively late start for a talented footballer, but the apprenticeship contract the club offered him was an important economic support. And there was pride, of course: he, the boy from Galilei Park in the Watergraafsmeer, was now an Ajax player.

He was a stubborn boy. One day, Louis crept into the unguarded Ajax stadium with a couple of friends and began playing on that magical grass

The Ajax reserves played on Saturday afternoons in front of crowds of around 3,000. Michels was ever present, and the players were acutely aware that the grumpy-faced “General” was judging and weighing the young footballers, often finding them wanting. There was no place for Louis in the first team: he was restricted to one appearance in a friendly versus RSC Anderlecht, in Brussels, in 1973. That was no disgrace, because his rival for the centre-forward spot was Cruyff – now mature, fast as an arrow, and on his way to becoming one of the best players in the world.

Cruyff as an obstacle: it would happen again. Nearly 50 years later, the always opinionated Cruyff remains a trenchant critic of Van Gaal, even though, essentially, they share a football philosophy. However, these two are different, if equally stubborn, characters.

Young Louis had a busy routine. Early in the morning he would ride his moped across town to Amsterdam-West for his gym teacher’s course. He would bring along bread, a bottle of milk and his football bag, and at the end of the day he would ride straight to the 7pm Ajax training session. Louis had a twofold mission: he wanted to be both an excellent gym teacher and a star footballer. Whether those things could be combined, he would find out later. He pursued his aim passionately and, though he wore his hair long, the Amsterdam hippie scene of the 1960s seemed to pass him by.

…

I first met Louis van Gaal on what was, in my own footballing dream, a very special winter’s evening. It was November 1971: I was an Ajax apprentice, walking into the changing rooms at the stadium for the first time, wracked with nerves before my debut training session. This was unknown territory. I found a spot, and soon afterwards a tall young man with a serious face approached me. His name was Louis van Gaal, and he inspected me from head to toe. I had the uneasy feeling I was being judged: who was I? What was I here for? Did I have the right kit with me? Who had given me permission to sit in this spot – his spot? I obediently moved up a bit, and Louis approved.

Twenty minutes later the trainer stuck his head around the door to tell us that due to the bad weather we would be training in the sports hall. Van Gaal saw my panic. Indoor training? This was new to me. “Don’t you have indoor shoes with you?” he remarked. Was his tone critical, disparaging or merely factual? For a newcomer like me, it certainly felt awkward. Another young reserve, Johnny Rep, who would play in two World Cup finals for the Netherlands, came to my rescue. I could borrow his spare pair of indoor shoes.

Two years later, in 1973, Louis left Ajax: he had concluded, realistically, that he was good, but not better than Cruyff. After a spell in Belgium with FC Antwerp he returned to the Netherlands, where he spent most of his playing career with Sparta Rotterdam, developing into a midfielder with tactical insight. But he never just played: he also studied and represented the footballers’ trade union. He taught gym at a high school in Amsterdam for “difficult” pupils, with whom he sometimes clashed and sometimes clicked, his authority provoking resistance as well as obedience. Either way, the experience would later serve him well as coach.

During the final years of his footballing career Van Gaal earned his coaching licence, and after a short spell at AZ Alkmaar as a youth coach, he was appointed manager at the Ajax youth academy. A few years later he became first team assistant coach to Leo Beenhakker.

From his first day as Ajax manager, he was convinced of the rightness of his vision. Sometimes he was called dictatorial and self-satisfied

In September 1991 Beenhakker moved to Real Madrid, and Van Gaal was promoted to the top job at Ajax. By this time, having retired from playing in 1979, I was working as Ajax’s press officer. The day after his appointment, Van Gaal called me in to his new office. “Can I trust you?” he demanded. There wasn’t an ounce of irony, let alone humour. What answer did he expect? A moment later I was installing my little desk directly opposite his own. We shared the office, and I was his lieutenant. He wanted me to be a middleman between the players and himself, a person they could confide in, a sounding board. That day was the start of seven unforgettable years. The climax would be victory against AC Milan in the Champions League final of 1995: for the first time since the early 1970s, the club from Amsterdam-East was the best in Europe.

From his very first day as Ajax manager, Van Gaal was convinced of the rightness of his vision. Sometimes this conviction slid into rigidity, and he was called authoritarian, dictatorial, self-satisfied. True, he loudly proclaimed his values, and true, he was strict: no reading during breakfast with the team; when you speak to someone, look that person in the eye; tuck your shirt into your shorts, and so on. But as far as he was concerned, his rules were more than mere doctrine; they made up a code of behaviour, a basis for collective responsibility. Louis van Gaal’s changing-room ethics were based on the values he had learnt at home.

Yes, he could be unbending in his views, and anyone who didn’t follow his line could count on his anger. But he was also clever. I remember the fright of the young Marc Overmars when, the day before a league match against Go Ahead Eagles, Van Gaal called him to the front of the group. “Marc,” he said, with characteristically raised voice, “you played for the Eagles. Explain what their strong and weak points are.” Nervously, Overmars did his best. Louis praised him, and talked more about the game. The next week another player was summoned to address the group. After a while, everyone came to these meetings prepared with a story about their opponent. The effect was twofold: the players overcame their fear of speaking before the group, and they went into games having studied the opposition in depth.

Monday mornings were legendary. If Ajax had won the previous day, Louis would greet all staff members with a firm handshake and the unvarying phrase, “Congratulations on your club,” again with that characteristically raised voice. It sounded exaggerated, and yet we came to realise that we all had a share in victory on the field; we were all Ajax. He also turned up every day to the youth academy, talking to coaches and players, building a sense of community: “Congratulations on your club.” After a while, people said it to each other, too – complete with raised voice.

At every level of the club, Van Gaal set ever higher ambitions before our eyes. The club became Dutch, European and world champions. Recently he showed he could do the same trick in a short time with the national team, guiding the Netherlands to an unexpected third place in the World Cup finals. I’m convinced that if Louis is given time and space he could create the same dynamic at Manchester United.

It’s true that the art of solving conflicts with diplomacy or a touch of self-deprecation is against his nature – hence his notorious outbursts of rage. I remember one occasion when a Dutch journalist asked the same question three times at a press conference. Eventually Van Gaal yelled, “Is it me who is smart, or is it you who is dumb?” During the World Cup in Brazil he showed that he has mellowed (a little): nowadays he might cap an explosion with a smile. But, as his Old Trafford squad will quickly learn, smiling or not, he is not a man who makes concessions.

David Endt is a sports writer and broadcaster