ˈoʊɪŋ tə ðə mˈɛntəl ɪŋkəpˈæsᵻɾi ʌv hɪz bɹˈʌðɚ sˌɜː lˈuːɪs ˌælɪɡzˈændɚ ɡɹˈænt ænd ðɪ ˈɜːlɪɚ dˈɛθs ʌv tˈuː ˈoʊldɚ bɹˈʌðɚz fɹʌm wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd ɪlˈɛvən hiː ˈæktᵻd æz kjʊɹɹˈeɪɾɚɹ ʌvðə ɡɹˈænt ᵻstˈeɪts ænd ðoʊz ʌvðə sˈiːfiːld ˈɜːldəm ʌntˈɪl hiː səksˈiːdᵻd æz ˈɜːl ʌv sˈiːfiːld ɪn hɪz ˈoʊn ɹˈaɪt ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd fˈoːɹɾi.
Owing to the mental incapacity of his brother Sir Lewis Alexander Grant (and the earlier deaths of two older brothers) from 1811 he acted as Curator of the Grant Estates and those of the Seafield Earldom until he succeeded as Earl of Seafield in his own right in 1840.