Purpose: Splenic flexure mobilization (SFM) is occasionally utilized during sigmoidectomy to facilitate a tension-free colorectal anastomosis. Present literature regarding its use, safety, and efficacy predominantly evaluates traditional laparoscopic vs. open techniques, thus not adequately representing the current minimally invasive surgical landscape. Methods: This retrospective cohort analysis evaluated SFM during sigmoidectomy for diverticular disease via traditional laparoscopic, single-incision laparoscopic, and robotic techniques at a United States academic institution from 2019 to 2022. Primary outcomes were the rate of SFM, independent predictors, and short-term outcomes. Results: A total of 117 patients underwent sigmoidectomy for diverticulitis by six colorectal surgeons, of whom 27 underwent SFM. SFM was associated with higher rates of complicated diverticulitis (85.2% vs. 46.7%, p < 0.001), including abscess (55.6% vs. 33.3%, p = 0.037) and fistulae (59.3% vs. 17.8%, p < 0.001). Presence of a fistula was an independent predictor of SFM by logistic regression (odds ratio [OR], 5.886; p < 0.001). Mobilization was associated with more concomitant surgical procedures (66.7% vs. 28.9%, p < 0.001). There was a significant association between SFM and conversion to open approach (14.8% vs. 3.3%, p = 0.049), longer length of stay (4.2 ± 2.8 days vs. 3.6 ± 4.3 days, p = 0.041), and increased operative time (241.7 ± 76.4 minutes vs. 199.2 ± 75.7 minutes). There was no difference in 30-day morbidity/mortality. Conclusion Routine SFM can be considered in minimally invasive sigmoidectomy for complicated diverticulitis without significant impact on 30-day morbidity/mortality regardless of surgical approach and may be anticipated preoperatively, particularly when a fistula is present.