Fe-doped SnO2 thin films exhibit ferromagnetism with a Curie temperature of 610 K and a spontaneous magnetization of 2.2 Am²kg⁻¹. The films are transparent and show atomic-scale magnetic inhomogeneity, with only 23% of iron ions magnetically ordered. The net ferromagnetic moment per ordered iron ion is 1.8 μB, higher than in any simple iron oxide. The high Curie temperature is attributed to ferromagnetic coupling via an electron trapped in a bridging oxygen vacancy (F-center). Fe-doped SnO2 thin films were grown using pulsed-laser deposition from Sn0.95Fe0.05O2 targets. The films are single-phase, well-oriented with a rutile (101) texture, and have a thickness of 100-300 nm. They are transparent with a faint brown tinge and show a red shift in optical absorption edge. The films are ferromagnetic at room temperature with moments ranging from 2-9 Am²kg⁻¹ and exhibit hysteresis. The Mössbauer spectrum shows all iron as high-spin Fe³+ with 88% magnetically ordered. The film is magnetically inhomogeneous, with only about one iron ion in four being magnetically ordered. The net ferromagnetic moment is 1.8 μB per ordered iron ion, and the ferric moment is 5 μB per ion, suggesting ferrimagnetic compensation. A novel ferromagnetic exchange mechanism, F-center exchange (FCE), is proposed, involving a spin-polarized electron trapped in an oxygen vacancy. This mechanism involves Fe³+ ions with an oxygen vacancy, where the trapped electron overlaps with the d-shells of both iron neighbors. The F-center resembles Kasuya's bound magnetic polaron. The study suggests that FCE is the dominant exchange mechanism in SnO2:Fe films. The average ferromagnetic moment per iron is reduced from 5.0 to 4.5 μB, and further reduction may occur from antiferromagnetic Fe³+–O²–Fe³+ superexchange bonds. In summary, Sn1−xFe xO2 is a transparent ferromagnet with a large net moment per ordered ferric ion and a high Curie temperature. The magnetic order involves extended ferromagnetic regions with some reversed spins and many isolated paramagnetic iron sites. Further research should focus on increasing the mobility of spin-polarized F-center electrons and developing links with high-k dielectrics.Fe-doped SnO2 thin films exhibit ferromagnetism with a Curie temperature of 610 K and a spontaneous magnetization of 2.2 Am²kg⁻¹. The films are transparent and show atomic-scale magnetic inhomogeneity, with only 23% of iron ions magnetically ordered. The net ferromagnetic moment per ordered iron ion is 1.8 μB, higher than in any simple iron oxide. The high Curie temperature is attributed to ferromagnetic coupling via an electron trapped in a bridging oxygen vacancy (F-center). Fe-doped SnO2 thin films were grown using pulsed-laser deposition from Sn0.95Fe0.05O2 targets. The films are single-phase, well-oriented with a rutile (101) texture, and have a thickness of 100-300 nm. They are transparent with a faint brown tinge and show a red shift in optical absorption edge. The films are ferromagnetic at room temperature with moments ranging from 2-9 Am²kg⁻¹ and exhibit hysteresis. The Mössbauer spectrum shows all iron as high-spin Fe³+ with 88% magnetically ordered. The film is magnetically inhomogeneous, with only about one iron ion in four being magnetically ordered. The net ferromagnetic moment is 1.8 μB per ordered iron ion, and the ferric moment is 5 μB per ion, suggesting ferrimagnetic compensation. A novel ferromagnetic exchange mechanism, F-center exchange (FCE), is proposed, involving a spin-polarized electron trapped in an oxygen vacancy. This mechanism involves Fe³+ ions with an oxygen vacancy, where the trapped electron overlaps with the d-shells of both iron neighbors. The F-center resembles Kasuya's bound magnetic polaron. The study suggests that FCE is the dominant exchange mechanism in SnO2:Fe films. The average ferromagnetic moment per iron is reduced from 5.0 to 4.5 μB, and further reduction may occur from antiferromagnetic Fe³+–O²–Fe³+ superexchange bonds. In summary, Sn1−xFe xO2 is a transparent ferromagnet with a large net moment per ordered ferric ion and a high Curie temperature. The magnetic order involves extended ferromagnetic regions with some reversed spins and many isolated paramagnetic iron sites. Further research should focus on increasing the mobility of spin-polarized F-center electrons and developing links with high-k dielectrics.