Early career

De Mos was born in The Hague, Netherlands on 27 March 1947. He played in the youth team of local club ADO Den Haag.^[1] he began his managing as an assistant to Leo Beenhakker at Ajax, and continued to do so while Kurt Linder was manager.

After Linder left, de Mos replaced him as Ajax manager in 1982, and retained the role until he was dismissed shortly before the end of the 1984–1985 season. With Ajax de Mos won the national championship twice and the cup once.

Successes in Belgium

After leaving Ajax, de Mos became coach of Mechelen in Belgium. There he won the national title, cup and, in 1988, the European Cup Winners' Cup, beating his former club Ajax 1–0 in the final. He also won the 1988 European Super Cup with the club.

De Mos left Mechelen after three years to become Anderlecht manager, where he again reached the 1990 European Cup Winners' Cup Final, this time losing to Sampdoria in Gothenburg.

PSV

In 1993, after his successful stints with Mechelen and Anderlecht, de Mos came back to the Netherlands and became the new manager of PSV Eindhoven, faced with the task of cleaning up an aging team. In his first season, PSV placed third in the league.

In his second season, despite some major purchases, PSV and de Mos did not perform well. In September 1994, he positioned the centre forward Erik Meijer, known for being able to make good headers, for incomprehensible reasons as a back against Bayer 04 Leverkusen.

Career decline

After leaving PSV, de Mos managed 6 clubs and one national team in the span of 10 years, not winning any major trophies. In that period, he managed Werder Bremen, Standard Liège, Sporting Gijón, Urawa Red Diamonds, Mechelen once again, Al Hilal and the United Arab Emirates national team. During that time, de Mos was only able to win the Belgian Second Division with Mechelen in the 2001–02 and promote the club back up to the Belgian First Division A.

Vitesse

De Mos ultimately ended up in Arnhem on the bench at Vitesse in 2006. He was signed at the last moment after the club failed to attract the Belgian manager Johan Boskamp, largely because Boskamp did not have the correct Dutch papers and no dispensation was given by the KNVB.

After a disappointing first season, Vitesse ended in 12th and in the subsequent play-offs they fought for a place in the UEFA Intertoto Cup. After successful matches against NAC Breda (3–2 and 0–1 wins) and NEC (1–0 and 0–2 wins), they lost in the final against Utrecht on away goals. The 2007–08 season began with some success. The team won their first three matches, which was the best start to a season in the club's history, however the season again ended in failure, finishing in 12th place again. On 28 April 2008, the club management announced that the contract with de Mos was dissolved immediately.

Work as a pundit

De Mos was regularly shown on television as a pundit on the former Talpa TV and the Belgian Sporza. During the 2006 FIFA World Cup in Germany, de Mos was as an analyst for the NOS and the Belgian VIER.

Kavala

De Mos signed a six-month contract with Greek club Kavala, with an option to extend it up to January 2010, following the sacking of Vangelis Goutis.^[2] Shortly after, he was followed by the signings of Denilson, Ebi Smolarek and Diogo Rincón during the winter transfer period.^[3] He found immediate success, most notably with an away win against Panathinaikos in February, with the Athens club leading the league table at the time.

His notable results in Greece, despite his short stay at the club, coupled with his trademark managerial style, led popular Dutch magazine Voetbal International to give him the nickname of "Koning van Kavala" (King of Kavala).^[4] On 2 April 2010, de Mos resigned from his position as manager, allegedly after disputes with the club owner.

Sparta Rotterdam

On 2 April 2010, only one day after his resignation from Kavala, de Mos was named new manager of Sparta Rotterdam, replacing dismissed boss Frans Adelaar. He arrived at a time when the club was facing relegation with only a one-point advantage over 16th-placed ADO Den Haag. His adventure at Sparta started with little success: a 1–1 home draw to Heracles Almelo was followed by two consecutive losses, with his side being overtaken by ADO Den Haag, forcing the Rotterdam team to take part to the post-season promotion and relegation tournament in order to maintain its place in the Eredivisie.

In the first leg of the relegation play-offs second round, Sparta were stunned by Eerste Divisie outsiders Helmond Sport, losing the game 2–1. Sparta then managed to get back from that loss by winning 2–0 in a dramatic return leg, thus ensuring them a place in the third and final round, in which they challenged crosstown rivals Excelsior in a two-legged derby for a place in the 2010–11 Eredivisie.

After the first leg ended 0–0 at Excelsior's home stadium, Sparta was eliminated in a dramatic return match, with Excelsior missing a penalty, and then Sparta scoring the 1–0 goal in injury time only to suffer an equaliser only seconds later. The game ended with a 1–1 draw, as Sparta was consequently relegated in the 2010–11 Eerste Divisie. De Mos left Sparta shortly after, stating that the results of Sparta did not match the wishes of both de Mos and Sparta's ownership at the time.

Manager

Ajax^[7]

• Eredivisie: 1982–83, 1984–85
• KNVB Cup: 1982–83

Mechelen^[8]

• Belgian First Division: 1988–89
• Belgian Cup: 1986–87
• Belgian Second Division: 2001–02
• European Cup Winners Cup: 1987–88
• European Super Cup: 1988

Anderlecht^[9]

• Belgian First Division: 1990–91
• European Cup Winners Cup runner-up: 1989–90^[10]

Individual

• European Football Coach of the Season: 1987–88^[11]
• Belgian professional Manager of the Year: 1986–87, 1988–89^[12]