Martin, although he lacked major political talents and was mistrusted by Thomas Pelham-Holles, 1st Duke of Newcastle, had a capacity for hard work and dealing with administration. This led to his being appointed Secretary to the Treasury for the first time in November 1756, during Legge's second Chancellorship. This was a post which was more administrative than political in nature, although Martin was an MP and the appointment was a patronage one. In April 1757 he left office together with his political allies, led by William Pitt the Elder.