An investigation of the α decay of Sm147 was performed using an ultra-low-background twin Frisch-grid ionization chamber (TF-GIC). Four natural samarium samples were produced using pulsed laser deposition in ultrahigh vacuum. The abundance of the Sm147 isotope was measured using inductively coupled plasma mass spectrometry. A combined half-life value for Sm147 of 1.079(26)×1011 yr was measured. A search for the α decay into the first excited state of Nd143 has been performed using γ spectroscopy, resulting in a lower half-life limit of T1/2>3.1×1018 yr (at 90% C.L.).