An agroforestry land use system aimed at improving the productivity of smallholder dairy farms using Calliandra calothyrsus and Sesbania sesban shrubs as feed supplements was introduced to semicommercial SDFs in Meru, Kenya, as part of a field trial. The objective of this study was to assess the impact of using the C. calothyrsus and S. sesban on family income and livelihoods during the 16-month trial period. Eighty farmers randomly allocated to four groups (nutrition, reproduction, combined nutrition and reproduction, and a comparison group) were enrolled in this study. The nutrition intervention included nutritional management advice and provision of 150 C. calothyrsus seedlings and 150 S. sesban seedlings to each farm. Farms were visited every 1-2 months during the trial to collect data on milk production and feeding practices during the previous day. Seventy of these farms completed the trial and were interviewed post-intervention. Partial budget analysis of their farms was done by comparing changes in average monthly profits (from milk) and feeding costs/cow for the first 6 months and last 6 months of the intervention. Focus group discussions were used to collect qualitative information on livelihood effects from the trial. There was a KES 2,380.3 (USD 23.5) increase in average monthly profit/cow in the nutrition group comparing the first and last 6 months of the trial, representing a 68.8% improvement (p = 0.02). Average feeding costs significantly decreased across all groups over the trial period. Knowledge on dairy cow nutrition, level of confidence on calf management, and feeling of empowerment to raise calves/heifers to achieve first calving by 27 months were higher among farmers in the nutrition and combined groups than farmers in the other groups. There were positive direct and indirect impacts on the income and livelihoods of farmers in the two groups receiving nutritional interventions. Agroforestry, using C. calothyrsus and S. sesban shrubs can improve household livelihoods if adopted by SDFs in Kenya.