diff --git a/examples/multibody/cassie_benchmark/test/cassie_bench.cc b/examples/multibody/cassie_benchmark/test/cassie_bench.cc
index 1c199ed127d7..7ac46a990cfc 100644
--- a/examples/multibody/cassie_benchmark/test/cassie_bench.cc
+++ b/examples/multibody/cassie_benchmark/test/cassie_bench.cc
@@ -33,6 +33,39 @@ drake::test::LimitMallocParams LimitReleaseOnly(int max_num_allocations) {
   return { .max_num_allocations = max_num_allocations };
 }
 
+// Track and report simple streaming statistics on allocations. Variance
+// tracking is adapted from:
+// https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Welford's_online_algorithm
+class AllocationTracker {
+ public:
+  AllocationTracker() {}
+
+  void Report(benchmark::State* state) {
+    state->counters["Allocs.min"] = min_;
+    state->counters["Allocs.max"] = max_;
+    state->counters["Allocs.mean"] = mean_;
+    state->counters["Allocs.stddev"] =
+        updates_ < 2 ? std::numeric_limits<double>::quiet_NaN()
+                     : std::sqrt(m2_ / (updates_ - 1));
+  }
+
+  void Update(int allocs) {
+    min_ = std::min(min_, allocs);
+    max_ = std::max(max_, allocs);
+    ++updates_;
+    double delta = allocs - mean_;
+    mean_ += delta / updates_;
+    m2_ += delta * (allocs - mean_);
+  }
+
+ private:
+  int min_{std::numeric_limits<int>::max()};
+  int max_{std::numeric_limits<int>::min()};
+  int updates_{};
+  double mean_{};
+  double m2_{};
+};
+
 // Fixture that holds a Cassie robot model in a MultibodyPlant<double>. The
 // class also holds a default context for the plant, and dimensions of its
 // state and inputs.
@@ -85,6 +118,7 @@ class CassieDoubleFixture : public benchmark::Fixture {
   }
 
  protected:
+  AllocationTracker tracker_;
   std::unique_ptr<MultibodyPlant<double>> plant_{};
   std::unique_ptr<Context<double>> context_;
   int nq_{};
@@ -94,57 +128,22 @@ class CassieDoubleFixture : public benchmark::Fixture {
   VectorXd x_{};
 };
 
-// Track and report simple streaming statistics on allocations. Variance
-// tracking is adapted from:
-// https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Welford's_online_algorithm
-class AllocationTracker {
- public:
-  explicit AllocationTracker(benchmark::State* state) : state_(state) {}
-
-  ~AllocationTracker() {
-    state_->counters["Allocs.min"] = min_;
-    state_->counters["Allocs.max"] = max_;
-    state_->counters["Allocs.mean"] = mean_;
-    state_->counters["Allocs.stddev"] =
-        updates_ < 2 ? std::numeric_limits<double>::quiet_NaN()
-                     : std::sqrt(m2_ / (updates_ - 1));
-  }
-
-  void Update(int allocs) {
-    min_ = std::min(min_, allocs);
-    max_ = std::max(max_, allocs);
-    ++updates_;
-    double delta = allocs - mean_;
-    mean_ += delta / updates_;
-    m2_ += delta * (allocs - mean_);
-  }
-
- private:
-  benchmark::State* state_{};
-  int min_{std::numeric_limits<int>::max()};
-  int max_{std::numeric_limits<int>::min()};
-  int updates_{};
-  double mean_{};
-  double m2_{};
-};
-
 // NOLINTNEXTLINE(runtime/references) cpplint disapproves of gbench choices.
 BENCHMARK_F(CassieDoubleFixture, DoubleMassMatrix)(benchmark::State& state) {
-  AllocationTracker tracker(&state);
   MatrixXd M(nv_, nv_);
   for (auto _ : state) {
     // @see LimitMalloc note above.
     LimitMalloc guard({.max_num_allocations = 0});
     InvalidateState();
     plant_->CalcMassMatrix(*context_, &M);
-    tracker.Update(guard.num_allocations());
+    tracker_.Update(guard.num_allocations());
   }
+  tracker_.Report(&state);
 }
 
 BENCHMARK_F(CassieDoubleFixture, DoubleInverseDynamics)
     // NOLINTNEXTLINE(runtime/references) cpplint disapproves of gbench choices.
     (benchmark::State& state) {
-  AllocationTracker tracker(&state);
   VectorXd desired_vdot = VectorXd::Zero(nv_);
   multibody::MultibodyForces<double> external_forces(*plant_);
   for (auto _ : state) {
@@ -152,14 +151,14 @@ BENCHMARK_F(CassieDoubleFixture, DoubleInverseDynamics)
     LimitMalloc guard({.max_num_allocations = 3});
     InvalidateState();
     plant_->CalcInverseDynamics(*context_, desired_vdot, external_forces);
-    tracker.Update(guard.num_allocations());
+    tracker_.Update(guard.num_allocations());
   }
+  tracker_.Report(&state);
 }
 
 BENCHMARK_F(CassieDoubleFixture, DoubleForwardDynamics)
     // NOLINTNEXTLINE(runtime/references) cpplint disapproves of gbench choices.
     (benchmark::State& state) {
-  AllocationTracker tracker(&state);
   auto derivatives = plant_->AllocateTimeDerivatives();
   auto& port_value =
       plant_->get_actuation_input_port().FixValue(context_.get(), u_);
@@ -169,8 +168,9 @@ BENCHMARK_F(CassieDoubleFixture, DoubleForwardDynamics)
     InvalidateState();
     port_value.GetMutableData();  // Invalidates caching of inputs.
     plant_->CalcTimeDerivatives(*context_, derivatives.get());
-    tracker.Update(guard.num_allocations());
+    tracker_.Update(guard.num_allocations());
   }
+  tracker_.Report(&state);
 }
 
 // Fixture that holds a Cassie robot model in a MultibodyPlant<AutoDiffXd>. It
@@ -198,7 +198,6 @@ class CassieAutodiffFixture : public CassieDoubleFixture {
 BENCHMARK_F(CassieAutodiffFixture, AutodiffMassMatrix)
     // NOLINTNEXTLINE(runtime/references) cpplint disapproves of gbench choices.
     (benchmark::State& state) {
-  AllocationTracker tracker(&state);
   MatrixX<AutoDiffXd> M_autodiff(nv_, nv_);
   auto x_autodiff = math::initializeAutoDiff(x_);
   plant_autodiff_->SetPositionsAndVelocities(context_autodiff_.get(),
@@ -218,18 +217,18 @@ BENCHMARK_F(CassieAutodiffFixture, AutodiffMassMatrix)
 
     compute();
 
-    tracker.Update(guard.num_allocations());
+    tracker_.Update(guard.num_allocations());
   }
 
   for (auto _ : state) {
     compute();
   }
+  tracker_.Report(&state);
 }
 
 BENCHMARK_F(CassieAutodiffFixture, AutodiffInverseDynamics)
     // NOLINTNEXTLINE(runtime/references) cpplint disapproves of gbench choices.
     (benchmark::State& state) {
-  AllocationTracker tracker(&state);
   VectorXd desired_vdot = VectorXd::Zero(nv_);
   multibody::MultibodyForces<AutoDiffXd> external_forces_autodiff(
       *plant_autodiff_);
@@ -255,18 +254,18 @@ BENCHMARK_F(CassieAutodiffFixture, AutodiffInverseDynamics)
 
     compute();
 
-    tracker.Update(guard.num_allocations());
+    tracker_.Update(guard.num_allocations());
   }
 
   for (auto _ : state) {
     compute();
   }
+  tracker_.Report(&state);
 }
 
 BENCHMARK_F(CassieAutodiffFixture, AutodiffForwardDynamics)
     // NOLINTNEXTLINE(runtime/references) cpplint disapproves of gbench choices.
     (benchmark::State& state) {
-  AllocationTracker tracker(&state);
   auto derivatives_autodiff = plant_autodiff_->AllocateTimeDerivatives();
   auto u_autodiff = math::initializeAutoDiff(u_, nq_ + nv_ + nu_, nq_ + nv_);
   auto& port_value = plant_autodiff_->get_actuation_input_port().FixValue(
@@ -291,12 +290,13 @@ BENCHMARK_F(CassieAutodiffFixture, AutodiffForwardDynamics)
 
     compute();
 
-    tracker.Update(guard.num_allocations());
+    tracker_.Update(guard.num_allocations());
   }
 
   for (auto _ : state) {
     compute();
   }
+  tracker_.Report(&state);
 }
 
 }  // namespace