Cattle grazing management strategies can vary widely and have important effects on ecosystem carbon storage, greenhouse gas (GHG) emissions and land requirements. Existing GHG life cycle assessments of beef production often lack refined details about grazing strategies and their associated impacts on ecosystem carbon and greenhouse gas dynamics. A partial life cycle analysis was conducted on an upper Midwest grass finishing beef production system that compared 2 different grazing management strategies. The approaches were: 1) a non-irrigated, high-density grazing system stocked at 1.0 AU/ha (100,000 kg LW/ha; SysA) and 2) an irrigated, low-density grazing system stocked at 2.5 AU/ha (30,000 kg LW/ha; SysB). Our life cycle boundary only included the grass-finishing portion of beef production. Steers were born in April, weaned in November, backgrounded for 6 mo and grazed until slaughter in November, the following year, with an average age at slaughter of 19 mo and a 295 kg HCW. We included GHG associated with enteric methane (CH₄), soil nitrous oxide and CH₄ emissions, alfalfa and mineral supplementation and farm energy use. We used 2 years of on-farm corrected data for soil and enteric emissions and animal performance from Lake City Research Center, Lake City, MI. The assumed boundaries for potential soil C loss or gain ranged from an emission of 3 Mg C/ha/yr to a positive sink of 3 Mg C/ha/yr. Enteric CH₄ emissions had the largest effect on overall GHG flux and this varied by year and grazing system. In years 2012 and 2013, enteric CH₄ was 89 and 49% of the overall flux for SysA compared with 72 and 65% for SysB, respectively. Both systems are net GHG sources when soil C sequestration is excluded. When soil C sequestration is considered, each grazing strategy has potential to be an overall sink. These results indicate SysA and SysB would have to sequester up to 1.0 and 2.0 Mg C/ha/yr to have a net zero GHG footprint, respectively.