Grant joined Hato Hone St John in 2006 after a 26-year career in the New Zealand Army and holds the rank of Colonel. For 23 years, he was CEO of the national firm Baldwins Law Limited.   

He currently chairs the Hutt Valley Orchestra and the Wellington Youth Orchestra; also playing trumpet and trombone in a number of groups. He is currently a part-time and relief teacher at Wellington College. 

He was a member of the Greater Wellington District Committee; a Trustee on the Central Region Trust Board for six years and was Deputy Chair. He served as a member of the Priory Board and was a member of the Risk and Audit Committee. He was instrumental in the establishment of FEDs in Hutt Hospital. Currently, he is a member of the Order Affairs Committee.  

Grant was appointed a Member of the Order in 2011 and advanced to Officer in 2019.