In 1928 Beel obtained his master's degree in law at Nijmegen University. Subsequently he applied for a better job, and managed to find one as a clerk in the municipality of Eindhoven, also in the South of The Netherlands, at that time a booming city as a result of the establishment of the Philips group. With his wife, his son and his mother-in-law he moved to Eindhoven in 1929 and lived there for more than fifteen years. Three daughters were born there. Beel's professional career progressed rapidly and in less than one year he became a principal clerk. As he had in Zwolle, Beel proved to be an industrious man. He continued his part-time lecturing at the Katholieke Leergangen, he published regularly in the legal press and in 1935 he obtained his doctorate in law at the Nijmegen University.
At the time of his resignation as a municipal civil servant in 1942, Dr. Beel was Director of Social Affairs and Deputy Town Clerk. Dr. Beel resigned because he opposed the German Occupation of The Netherlands. To avoid being taken prisoner by the German occupational forces he frequently had to go in hiding. Eindhoven was liberated on 18 September 1944 at the time of the World War II military offensive known as Operation Market Garden. Dutch resistance fighters, massively manifesting themselves immediately after the Germans had gone, saw Dr. Beel as one of them. He became the spokesman of a group of prominent citizens in Eindhoven, who had resisted the Nazis during the war. The group was not in favour of a continuation of the pre-war political party-lines, with the ever-dominant Anti Revolutionary Party. In this vein they sent an Address, drafted by Dr. Beel, to Queen Wilhelmina, who still resided in London. Dr. Beel was urged to accept the function of adviser to the Military Administration (Militair Gezag), the temporary government in the liberated southern part of The Netherlands under Supreme Headquarters Allied Expeditionary Forces (SHAEF). In this capacity Dr. Beel was invited by the Dutch government in exile to travel to London and to advise on dealing with the war victims. He arrived in London on 1 January 1945. On 10 January he visited at her request Queen Wilhelmina in her English mansion Mortimer. This visit gave a decisive turn to Dr. Beel's life.
The Queen intuitively saw in Dr. Beel, a Roman Catholic from the South who ostentatiously had rejected Nazism, the prototype of the patriot and of the sort of "renewed" person she was looking for to replace the members of her war-cabinet, of whom she no longer wholeheartedly approved. Dr. Beel was promptly appointed Minister of the Interior in the third Gerbrandy cabinet. This cabinet resigned immediately after the end of the war, in May 1945, to free the path for a new one to be formed by two a liberal, Willem Schermerhorn, and a socialist, Willem Drees. They invited Dr. Beel to remain as Minister of the Interior in their cabinet (the cabinet Schermerhorn Drees). According to his own words, Dr. Beel reluctantly agreed. He moved with his family from Eindhoven in the South to Wassenaar in the West, a villadom close to The Hague, the government's residence.
Post-war parliamentary elections could finally be held in May 1946. In the election campaign Dr. Beel voiced the political resistance from the religious and liberal parties against the economic planning and socialism favoured by Prime Minister Schermerhorn and his political supporters. Unlike the British elections of the previous year where the Labour Party gained a decisive victory, in the Netherlands the 'Socialist breakthrough' which had been expected did not materialise in these first post-war elections. The Katholieke Volkspartij (KVP) (Roman Catholic People's Party) was the big winner, though no party had an overall majority. Queen Wilhelmina requested Dr. Beel to form a new cabinet. He became Prime Minister of a 'red-Roman coalition', which he called the 'New Truce', since it was the first cabinet in Dutch history of socialists and Roman Catholics. This Beel-cabinet set the course for the political and economic development of the post war Netherlands.
In 1948 parliamentary elections were again required for a constitutional renewal, which was thought necessary to solve the problems emerging in the Dutch East Indies, where the nationalists Sukarno and Hatta had proclaimed the independence of their country immediately after the Japanese surrender. The KVP won again and Dr. Beel was asked to form a new cabinet. He might again have become Prime Minister, but he failed to form the broad based cabinet of socialists, Catholic parties and liberals, which he deemed necessary to secure the corrections in the Constitution. J. van Schaik, a fellow KVP politician, took over and succeeded in forming a broad based cabinet by offering the socialist Willem Drees the function of Prime Minister, Schaik himself being satisfied with the function of Deputy Prime Minister. Drees appointed Dr. Beel High Commissioner of the Crown in the Dutch East Indies (now Indonesia), as a successor to Lieutenant Governor General Dr. Hubertus Johannes van Mook, a man of proven managerial abilities, who had to resign unwillingly.
The Dutch government in The Hague made several attempts to reach an agreement with the Republic of Indonesia. Dr. Beel, stationed in Batavia (now named Jakarta), was not in favour of such an agreement because of his suspicions - later proven to be right - that the new Republic did not want the establishment of a Federal State of Indonesia, as was planned in the Dutch decolonisation policy. Under the auspices of the Security Council of the United Nations an agreement was achieved in May 1949 to hold a Round Table Conference in The Hague in order to prepare the transfer of sovereignty. Dr. Beel made efforts to thwart the agreement. However he was unsuccessful and he resigned from his Office of High Commissioner of the Crown.
Dr. Beel returned to his home at the end of May 1949 and a few months later he accepted a professorate in administrative law at his Alma Mater in Nijmegen, one of his early ambitions.
On 7 November 1951, J. van Maarseveen, Minister of the Interior, suddenly died. Prime Minister Drees appealed to Dr. Beel to return to office. Again reluctantly, Dr. Beel accepted Prime Minister Drees' offer. He also held the function of Minister of the Interior in the next Drees-cabinet after the elections of 1952. In July 1956 Dr. Beel asked that he be allowed to resign from government to become, as a private citizen, chairman of a committee of three wise men that was requested by Queen Juliana and the Consort Prince Bernhard to help solve problems pertaining to the Royal Family. The problems were related to faith healer Greet Hofmans, whom the Queen had invited to the royal palace in order to cure her youngest daughter, who had been born half blind in 1947. The renowned German magazine Der Spiegel had accused Mrs. Hofmans of playing a 'Rasputin' role in the Royal Family. Within a month the committee had fulfilled its task by writing a secret report, which banished the sensitive affair from publicity. Three months later Dr. Beel was appointed Minister of State, a prestigious title of honour.
In 1958, after an interlude of eighteen months without a public office, Dr. Beel was appointed member of the Council of State. Soon afterwards however he was called upon to form his second cabinet - an interim cabinet from December 1958 until May 1959, that had to dissolve parliament and call new elections. After these elections Dr. Beel assisted the Roman Catholic politician Jan de Quay in forming a Catholic-liberal cabinet, ending for the time being the 'red-Roman coalition', which had been Dr. Beel's own initiative in 1946. The De Quay cabinet appointed Dr. Beel as Vice President of the Council of State, the most prestigious office in the Dutch administration, the head of state being the honorary President of the Council.
Whereas other political leaders, who had come forward after the war, one by one left the political scene and the 'participation-democracy' of the New Left movement created a new type of politician, Dr. Beel retained in the authority of the Council of State a great influence on government. He owed his role to the way he performed his high office as well to his position of confidence with the Royal Family. In various affairs the royals faced, Dr. Beel's taciturn way of acting on behalf of the monarchy and his prudent pulling the strings behind the scene as Vice President of the Council of State gave him the nickname 'The Sphinx'. The power he derived from both positions christened him "Viceroy of Holland". The authority of Dr. Beel and his controlling influence in political circles became manifest when new cabinets had to be formed or cabinet crises had to be warded off. Through the thirteen years of his vice-presidency Dr. Beel had a steering hand in nearly every cabinet-formation - including the dramatic formation of the cabinet of the social-democrat Joop den Uyl in 1973.
As from the first of July 1972, at the age of seventy, Dr. Beel resigned (prematurely) from his office of Vice President of the Council of State. Some years before his wife had died. He retired with his mentally handicapped eldest daughter and her attendant to the quiet village of Doorn. On 11 February 1977 Dr. Beel died in the University Hospital of Utrecht.