He was a son of Adelheid (née Herz) and Carl Mayer von Rothschild.

[5] After studying law, he joined the family banking firm M. A. Rothschild & Söhne in Frankfurt.

Following the death of their uncle Amschel Mayer Rothschild, Mayer Carl and his brother Wilhelm Carl von Rothschild became heads of the firm.

He was appointed the Duchy of Parma consulship in Frankfurt, Consul of Bavaria and Austrian Consul-General and, in 1866, he took part in a Frankfurt delegation to Berlin to demand a reduction in the contribution to the war effort, was a deputy in the North German Diet, a member of the German Reichstag and took a seat on the Frankfurt city parliament.

[5] In 1871, Rothschild became the first Jewish member of the House of Lords of Prussia.