This paper presents the effects of catch crops (white mustard, lacy phacelia, and a mixture of legumes—faba bean + spring vetch) and two tillage systems (plough tillage and no-tillage) on some quality parameters of spring wheat grain. A field experiment in growing spring wheat in monoculture was conducted in the period 2016–2018 in Czesławice (central part of the Lublin region, Poland). An assumption was made that the nutritional composition of wheat grain could be influenced already at the stage of selection of agronomic practices by modifying the soil chemical and enzyme composition—being the “starting point” for grain quality. It was proven that all the catch crops tested in this study contributed to an improvement in the chemical composition of the soil used in the experiment (a significant increase in humus, P and Mg content). Both the catch crops and the conservation (no-tillage) system stimulated the activity of soil enzymes: dehydrogenase and urease. This resulted in more favorable soil conditions for spring wheat grown in monoculture. The cultivation of the catch crops (particularly white mustard) indirectly contributed to an increased content of dietary fiber and o-dihydroxyphenols in wheat grain. Moreover, the content of most of the amino acids determined and the essential amino acid index (EAAI) in wheat grain were found to be more favorable in the treatments with the catch crops. The highest content of all the macro- and micronutrients analyzed in wheat grain was found in the catch crop treatments (especially that with white mustard). It should be noted that spring wheat responded favorably to the reduced tillage system (no-tillage). Since the grain content of o-dihydroxyphenols, magnesium, calcium, copper, manganese, iron, selenium, and some amino acids (especially essential ones: Lys, Met, Trp) was found to be higher compared to plough tillage.