We report high-resolution angle-resolved photoemission studies of epitaxial thin films of the correlated 4d transition metal oxide ferromagnet SrRuO 3. The Fermi surface in the ferromagnetic state consists of well-defined Landau quasiparticles exhibiting strong coupling to low-energy bosonic modes which contributes to the large effective masses observed by transport and thermodynamic measurements. Upon warming the material through its Curie temperature, we observe a substantial decrease in quasiparticle coherence but negligible changes in the ferromagnetic exchange splitting, suggesting that local moments play an important role in the ferromagnetism in SrRuO3. © 2013 American Physical Society.