Appointed as president of Fort St. George on 11 January 1744, Morse's short tenure was marked by Anglo-French tensions resulting from the ongoing War of the Austrian Succession.

On 7 September 1746, a French Navy fleet under the command of Bertrand-François Mahé de La Bourdonnais appeared near Madras and started besieging the settlement.

However, in October 1746 a violent storm forced La Bourdonnais's fleet to withdraw to Pondicherry, leaving Joseph François Dupleix in control.

Dupleix reneged on La Bourdonnais's terms, imprisoning the EIC garrison and British civilians along with looting Madras.

Morse had one daughter, Emilia, who married EIC official Henry Vansittart in 1754; after the marriage, she lived in England at Foxley's Manor in Bray, Berkshire.