This study examines the relationships between Greek macroeconomic variables, examining before and after the euro’s introduction as a currency. We conducted an extensive analysis from 1980 to 2019, examining various economic indicators such as government expenditure, unemployment rates, taxation, inflation, and national debt, employing causal and correlation analysis and econometric modeling with and without time-varying effects. The results revealed a significant correlation between the introduction of the euro and a tighter relationship between government spending and unemployment levels, while one more remarkable point was that higher government spending or debt reduction initiatives appeared to positively impact joblessness, particularly in the context of the euro. Our research underscored the correlation between national debt and government spending as increased debt led to reduced government expenditure and vice versa. Unemployment cited an increased impact on government spending right after the euro adoption, and on the other hand, the effect of unemployment on government spending decreased. The debt–government spending nexus was decreasing for many years before the euro adoption, while just before the euro adoption, the relationship between debt and government spending was rather stable. Finally, during the euro adoption, the effect of inflation on tax increased, while the corresponding inflation tax remained stable. Our findings have significant implications for policymakers shaping the economic strategies in Greece as they point out the necessity for stable and balanced approaches that manage government spending and debt to address unemployment effectively.