Although he never saw active service in the field during the two world wars, he became Chief of the General Staff in command of the Union Defence Force in 1949.

[1] In 1914, after four months service at the Military School in Bloemfontein, Beyers was appointed to the Permanent Force with the rank of lieutenant.

[1] While Beyers was a staff officer to the Cape Peninsula Garrison in 1922, he saw active service on the only occasion in his entire life.

[1] On his return to South Africa in 1927, Beyers was appointed officer instructor at the Military College at Roberts Heights.

Beyers gave up his post as Adjutant-general in 1945 owing to ill health and was placed on the retired list four months later.

The reason for his resignation was the interference in military matters and appointment of staff without consultation by Frans Erasmus, the Minister of Defence.

Before resigning, Beyers had lengthy correspondence with both Erasmus and the Prime Minister, D. F. Malan, on the matter:[1] My resignation was in fact tendered as far back as November 1949, in protest against the unconstitutional and unwarranted interference in the functions of the Chief of General Staff who, in fact and in law, is the Commander-in-Chief of the Forces in South Africa.

The facts are that the Minister sought to change the strategic dispositions of units and to appoint, promote, and transfer both officers and other ranks, without sufficient knowledge of their qualifications and without reference to the General Staff, of which I was the head.

[1] The fact that at times he acted as Chief of the General Staff during the Second World War indicates that Van Ryneveld had immense trust in Beyers' abilities.